What we need is Dell to release their 8800m GTX model (just to keep things competitive with Alienware) then have someone figure out a mod to make it work in the i9400/E1705/M1710 Hey we can all dream can't we?
The best users of the old inspiron/precision series can hope for is that the cards from the M6300 would be backwards compatible with the old motherboard, since they use the same form factor (at least, according to the diagrams i've seen). Surely with the release of the 8800M cards, a Quadro variant should also be on the horizon (reportedly the 2600M and the 3600M) with very similar architecture, but with OpenGL optimization. I know people already said that it won't work b/c the mobo BIOS is incompatible (which was the issue when putting a 7900 GTX in a M170), but it hasn't been tried yet (placing a 1600M in a M1710/M90/E1705 Mobo)...
...and we do need more bios hackers in this community