Well I have the DRM Andys & Skyth ... Like'm and certainly believe you could work out a Necron or 'Nid army ... I think E/W making some sort of Robo Skellys with hi-tech weapons, etc. as mentioned is an excellent idea ("Plan C"). For a lot of reasons ... Besides you can't have too many alien killer android types ...
I'm really not sure where WGF Deathbots are going ? And if they come thru ... fine, I'll have F/W Chaos Andys, DRM, E/W & WGF Andys ... it's a big galaxy/universe. I think too many are "wedded" to the idea that you have to have exact doppelgangers of G/W Necrons & 'Nids.
There are obvious reasons why that may be a problem ... However, if the lovely Greens of both armies mentioned, that E&C posted goes "Plan B", ie. "Covert Casting" ... That would be very acceptable ... At this point we already have an "Underground Railroad" established for this sort of operation.
Compounded by F/W's recent decision, I believe those who can excute/active Plans B & C should do so. That may be easier said then done.
I think, and don't kid yourself, there is a very, very good chance(98%+), IMO, the only Epic scale models that will be in the F/W catalogue will be AI by 2010. Don't count the Tony's Titan Game ... that at this point is a little more then wishfull thinking/day dreaming. And really won't affect the 'Nid/Necron situation ...