While I'm not particularly up to date on mobile GPUs, these seem to have rather interesting options around that price range in 15" or 17":
http://www.alienware.com/products/no...computers.aspx
Personally i find 17" too much, but if mobile gaming is your thing dual 3870s at $1650 looks appealing:
http://www.alienware.com/customize/M...de=SKU-DEFAULT
Then again i'm unsure if those can top a nice single chip nvidia, I guess some research would be needed.