The problem is, a less than 10% shader bump on the 480gtx isn't going to do much, infact with the same fairly low bandwidth on Nvidia Fermi's it would likely be a bit more bandwidth starved than a 480gtx so would likely not scale well.
Though end users are overclock memory ok, Nvidia's seemed very reluctant to up memory speeds, though maybe it kept them down on the gf104 just to keep it further away from a 470gtx and leave a larger amount of performance for a 384shader version.
The thing is, a 475gtx in the past 3 months could have made Nvidia a lot of money. Instead of £200 470gtx's that lose a bucketload, they could have been selling 15% faster full GF104's for maybe £200, and making more profit, instead they've stuck to three minimal profit/massive loss making cards in the two 460's and 470 cards.
The last three months, when AMD had nothing between £120 and £200 worth buying, is the time Nvidia most likely would have capitalised on a full GF104 IF they could.
WHich really does suggest they can't make full gf104's, which is pretty shockingly bad.
Why with a awful yield having issues gf100 they decreased the granularity by increasing cluster size I don't know. Whatever they are doing at 40nm, they are doing wrong with lots of failed parts on a waifer, going from 32 shaders on the GF100 to 16, or staying at 32 on the GF104 would likely have increased yields and increased the amount of shaders they could release with a decent yield.
At this point I really doubt we'll see a 384 shader GF104 or a 512 shader GF100 except in "extreme stunt" quantities, IE a launch, and a few dozen around the world, then nothing.
I've been saying it for 2 years now, what we need is Nvidia with a small core strategy/design, so they can actually compete on price with AMD. At the moment AMD aren't making huge margins on anything but the 5870, the 5850 is pretty expensive to make but I'm sure could come down another £15, theres just no need to, Nvidia can't go lower than it has now and with the GF104 can't come close to matching 5850 performance.
If AMD manage to push similar performance from a 336mm2 5850 core, into a circa 200mm2 core(i'm not sure that is the case, but looking increasingly likely) then Nvidia are quite literally boned. They can sell a 200mm2 core in a £150 with a healthy profit and beat 460gtx performance easily, while Nvidia would make a decent loss at £150 for something 20-30% slower.