I decided I'd have a go at a campaign idea for WHFB. me abd two friends have playtested this already and it worked quite well:

This fluffy campaign revolves around relatively small games of Warhammer, ranging from 300 point to 2000 point games. Three forces should be represented here with, if possible, one good force (Empire [Not Marienburg], Lizardmen, High Elves, Bretonnians and Dwarfs), one neutral force (Wood Elves, Ogre Kingdoms, Tomb Kings, Dogs of War and Marienburg) and one evil force (Dark Elves, Skaven, Vampire Counts, Chaos in any of its forms and Orcs & Goblins). What follows are the list of games which should be played to represent the happenings of the campaign. Depending on who wins the game, the scenarios will change.

1) First Encounter
In the first encounter, all three forces will set up in a triangular board, with no terrain except for a small hill/mound in the centre of the board (which should be 36� by 36� by 36� if possible, with 6� deployments for each side). The objective of the game is to simply hold the objective at the end of the game. This objective will be an enemy model represented by a race that none of the players is playing as. This model is supposedly a contact who knows all positions of the three armies’ camps. If the Good or Neutral team wins, then go to “Negotiations�. However if the Evil team wins, then go to “Raid the Enemy Camp�.

2) Negotiations
Because the Good or Neutral player has defeated his/her enemies at the first encounter, that general knows the positions of the two opposing player’s camps. The generals now decide to negotiate. The rules are as such:

Both Sides:
• One Hero armed with sword, light armour, shield, and up to 25 points worth of Magic Items
• 200 points of “Elite Infantry" (these may be Core, Special, or Rare infantry troops, as appropriate for the army in question, eg. Empire Greatswords, High Elf Phoenix Guard, and Dwarf Longbeards); any number of Champion models may be selected.

The skirmish takes place in a 24" x 24" area containing an overturned table and a grassy hillside. The area represents the negotiating area and surrounding vicinity.

Talks of peace between the three infamous Generals have broken down, and a duel to the death is imminent. The three armies are camped very close, and tensions are very high. The side that causes the other forces to rout from the negotiating area is the winner.

Place the Captains in the centre of the field and 1" apart. Each surrounding group of bodyguards should be deployed in a rough semicircle around their Captain on their half of the table. The bodyguards must start the game at least 6"away from the fighting Captains and no closer than 2" to any of the enemy bodyguards.

Each player rolls a D6. The higher scoring player gets to choose whether to go first or second.

This scenario uses the special rules detailed below:
Lose Your Nerve
At the beginning of the game, open conflict has not yet erupted. Honour dictates that the negotiating table is neutral ground where diplomats are safe from harm. Neither side wishes to be the first to violate this sacred rule of battle.
At the beginning of your turn, roll a D6 for each of your bodyguards. Keep track of the number of 5s and 6s that you roll. When the number of 5s and 6s is greater than the number of bodyguards you have, make a Leadership test for every bodyguard. If even one of them fails, your troops lose their nerve, break the truce, and charge their opponents.
The force that broke the truce is at a -2 Leadership for the Rout test, because this dishonourable act affects its morale.
Don't Make Any Sudden Movements
Before conflict breaks out, players can move their bodyguards only 2" per Movement phase and cannot come within 1" of an enemy model. The Captains must stay face-to-face within 2" of each other.
If the player who won ‘First Encounter’ (The good or neutral at this stage), proceed to “Underhand Alliances�. If the other good or neutral player wins, then proceed to: “Stalemate at the Crossroads�. However, if the Evil player wins, proceed to: “Raid the Enemy Camp�.
3) Raid the Enemy Camp
Because the Evil player has found the location of the two enemy camps, He will not hesitate to launch a raid or attack on them. The Good and Neutral forces will have to ally together to sustain the full might of the evil force. The Evil player should take a standard 2000pt army list, with NO special characters. The Good and Neutral player should take 1000pts each, to make a contingency army of 2000pts. The table should be 60� by 48�, with a 12� Deployment for each side. The table should be fairly covered with terrain which represents that the Good and Neutral players are defending a camp, so this includes hastily built ramparts and tents. If the Evil player wins, proceed to “Retreat to the Castle!� and if the Good and Neutral players win, then proceed to “Stalemate at the Crossroads�.

5) “Underhand Alliances�
The Good and Evil or Neutral and Evil Players will now be forced to ally because of the seemingly indestructible army of the enemy. The large army of the current winner, either Good or Neutral, will march on the unprotected forces of the weakened pair. The two weakened allies will attempt to catch the enemy off-guard using an ambush, to thin the enemies’ ranks before the coming battle. In a thin 24� by 48� board, line the Winning army (2000pts) in a convoy formation on a path down the middle of the board. Then, in a small 6�x12� on the left and right sides of the board, place 500 points of each allied contingency ready to ambush the convoy. The ambushers will be granted first turn for catching the Winning player’s force off-guard. If the Alliance wins, proceed to “The Final Encounter�, where the Single player will be at a disadvantage, as explained in the following text. If the Alliance is defeated, then proceed to “Retreat to the Castle!�

6) Stalemate at the Crossroads
As the Alliance (whichever one) has defeated the larger enemy force, the forces are at a stalemate. They meet at a crossroads, all ready for battle, but against who? The Alliance was only formed to fend off the larger enemy, and now the three forces (1000pts) are back on even terms. The three now fight on a three-way board (see “The First Encounter�), but this time with several pieces of terrain from the set you have chosen. This battle could determine who wins this campaign, and so the winner of this battle will go into “The Final Encounter� with +1 Leadership for all units within 6� of a Hero. No matter who wins, proceed to “The Final Encounter� with the +1L rule in place.

7) Retreat to the Castle!
The Alliance (whichever one) has been pushed so far back they have been forced to garrison in a nearby local castle/fortification. It is partially ruined, so appropriately place some makeshift barricades on the board to represent this. The Attacker will besiege the castle, using 2000pts, - plus a siege tower. The defenders will use 1500pts and all Core Units will be at -1L for all Panic (caused by another unit fleeing or being annihilated) Tests in the game. The Castle will span the whole board width (48�), and will be placed 18� into the board. The Defenders have a 12� Deployment inside the castle walls. The attackers will be placed on the opposite side of the board, 12� in (this is 42� inches form the castle walls). All rules for equipment are in the appendix of the Warhammer Rulebook, 6TH EDITION. If the alliance wins, go to “Stalemate at the Crossroads�. However, if the Single Player wins, then all Core Units in the following “Final Encounter� game will be at -2 Initiative because they are exhausted after fleeing from the castle walls.

The Final Encounter
This is the last battle, as the exhausted sides fight to the death for the final time. Once again, on a three-way board (See “The First Encounter�) the forces fight. The three force generals are confident that they can win at this stage, and they will field their best armies (1500pts, 2 Rare Choices Allowed). Special Rule: On top of any modifiers earned from previous games, if a general is killed in battle, the player who killed him gains 200 extra victory points, plus the dead general’s army is now at -1 Leadership for the rest of the battle (Excluding Rare Choices.) The army that wins this battle, is the winner of the campaign (because he has defeated his enemies, and the spoils of victory goes to them. However, depending on the amount of battles won by each side, shows who has won the tournament overall.

The Negotiations scenario actually uses some rules from Warhammer skirmish. It is very long, but basically, Is it any good? Because it's my first try at anything like this.