Welcome to Librarium Online!
I was kickin' this idea around for fun in smaller games:
By taking two Big Meks, for each one you may take a Deff Dread as a Troops choice. So you take 2 Dreads for Troops, then max out Killa Kans under Heavy Support. Even with a lot of upgrades, thats still only in the realm of 900pts. I figure throw in some buggies and you would have a very fun 1000pt list.
Didn't stick this under the list section because I wasn't being list specific; just thought "Da Dread Mob" would be fun in a normal game.
"It takes a vast amount of self control to be this dangerous."
---Ogvai Ogvai Helmshrot, Jarl of Tra, VI Legion Astartes
Get some mega nobz and paint them in same way as dreadnoughts and kans and you'd get a cool looking "dread mob" with way too much PK's, I think.
I play the exact list your mentioning in 1000 pt games. Opponents find it fun, and fluff, I have yet to get any complaints yet. I use the below. Its in theme, opponents always laugh when they see it, and its honestly not that survivable due to max armor 12. I like to take 1 big mek with a shokk attack, the 2nd with the KFF. Opponents have encouraged me to take 2 shokk attack guns, but this weekend I used 1 too great effect in a 3K game, and could only imagine if I had 2. Having 2 could really swing the game in the ork players favor in a small game.
HQ 2x Big Mek,
Troops: Dread with Big Shootas x2, Dread with additional CCx2
Heavy: 3x 3 Killa kans with rokkits.
For the remaining points I rotate between buggies and dethkoptas.
40K-Beakies(9-14-4),Guard(4-7-2),Orks(34-12-11). FANTASY-Dwarves(15-6-7),Beasts (14-14-1), Skaven (17-17-10) DoC (6-1-2). CYGNAR (28-15-1)