what laptop video card is equal to a *desktop* 256 mb 6800GT?

[slugg]

My current desktop specs:

6800 GT 256 mb
Athlon64 3200+
1.5 gb DDR333

^^ I want to replace all that with a laptop. A 15 inch screen would be nice, but a 17 is probably what I'll be stuck with. If possible, i'd like a laptop that can underclock/undervolt for normal useage (non-gaming) so I can get SOME type of battery life.

So what am I talking here? I'm not loyal to any brands at all, so dont be afraid to offer ATI based graphics chips or Intel based laptops, etc.

 

[Brainonska511]

Dell - XPS M170 (if you can get one off of the Dell Outlet with a Go 7800GTX) or the new XPS M1710 with the Go 7900GTX.