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Necron Lord with Warscythe, Veil of Darkness, Gaze of Flame and Lightning Arc.
10 Flayed Ones
3 Scarab Swarms
At the moment, ist sort of half shooty and half combat, although really you need to go all out on one or the other.
For a combat list, give the lord a destroyer body, ResOrb, and phase shifter, but no warscythe.
Take 2 units of 3 wraiths, and a unit of 4 scarab bases.
also, 2 units of 4 flayed ones, then the usual 20 necron warriors. comes to just under 1K
Or, for a shooty list. Lord with ResOrb and the veil.
Put him in a ''bodyguard'' unit of 8 immortals
Then the 20 warriors. 3 destroyers will be handy, and one Heavy. 999pts
In regards to the Deciever's second list:
I'd almost never take a single necorn model- including heavy destroyers. It means you have no chance of WBB- one of the Necron's best abilities.
As enemy firepower at 1000 pts isn't likley to be too devastating (at least not to necrons) I'd drop 2 immortals, and probably the res. orb as well to take a second heavy destroyer. This may seem a bit of a sacrifice, but I'd go either 2 HD's or none (you could take a few scarabs with disruption fields instead- the volume of attacks makes them surprisingly good against tanks).