hehe, that would be why I mentioned the shockingly obvious 470gtx bargain threads where they dropped them to £270, would be awful buys as they clearly just wanted to shift as many for as much as possible just before the 460gtx came along and made them a almost pointless purchase.
Its a hard call, my guess would be soon actually, but I don't think it will be a 485gtx, no idea what they'll call it. Theres one shader cluster disabled on the 460gtx, meaning they've got space for another card. Either Nvidia really have monumental issues with the process, or they've got PLENTY of full shader cluster parts waiting to go. So either they've got them being stockpiled and just want to clear up all remaining 480/470gtx cards on the shelves before releasing maybe a 475GTX or something. Maybe with the extra 10% shaders, and higher default clocks.
The other option is that their 60% bigger Fermi GF100 was impossible to get a full part out of, well in any quantity they could release a product as, and a part now smaller than a 5870 core still can't get a fully working part out. My bet would be stockpiling till the 480/470/465gtx are sold out, if its the later, if they still can't make them, they are truly and utterly retarded.
Theres also the potential for a new GF100, based on the GF104 design with a few extra clusters, somewhere midway between GF104/GF100 size, so maybe 400-440 shaders somewhere, which would put it somewhere like 15-20% faster than the current 460gtx.
A 512sp GF100 is a possibility but incredibly unlikely. They'd be making entire wafers to get a few cores while the cut down versions aren't viable options and can't be sold, if they've got a few thousand stockpiled, it will make for a very unhappy fanbase if no one can buy its "top" card. What I can't see, in ANY circumstance, is a "refresh" 485gtx, that would be a gf100 with higher clocks and all the shaders, certainly not anything with more than 512shaders, that has literally no chance till 28nm, which for Nvidia/TSMC, looks to be Q3 next year.