However, in the IGN E3 interview with Nathan Camarillo he hinted that the might be DX11 support in CE3 and Crysis 2. I believe his exact words were something like "I can't talk about that, but we at Crytek are always pushing the limits of gaming so... draw your own conclusions."
So DX11 is very possible.
And for crying out loud... Don't use Nvidia for high performance gaming...