Possibly but I have my doubts. The 8600 and 2600 are kind of the de facto PC GPUs for "being close to console performance" when it comes to PC versions of multiplatform games (but not necessarily optimized). I don't think they'd require something like an 8800 or 2900 only to "recommend" something that is at the most 20 to 30% faster. Also there are were very few models of the 8800 and 2900 series that had only 256 MB of VRAM, only a handful IIRC.
This does lead me to wonder though: how come we don't see more ATi technology partnerships with games that are ported from the 360 to the PC?
*Sorry for the double post*
I could be just like the x1900 vs the 7900s. The x1900s are now faster in modern games than the 7900s.