Not sure if I really want to get involved in this thread, but anyway, I'd like to comment on two things:
The 'disabled functional units' that Anandtech refers to, aren't some kind of 'magical' or 'hidden' features of the Fermi architecture. It's just a reference to the disabled Cuda cores, which everybody is probably well aware of. Namely, the GF100 design has 512 cores, but only 480 enabled on current cards at most. And the GF104 has 384 cores, but only 336 enabled.
This amounts to 6.7% or 14.3% extra processing power respectively, in theory, assuming perfectly linear scalability.
A while ago, a 512-core GF100 card was tested, and the practical speed improvement was more along the lines of 5%.
So, yes, there is room for improvement with Fermi, and yes, as the manufacturing process matures, they will be able to enable more cores (and perhaps even bump the clockspeed a bit)... but no, it's not going to be a dramatic improvement.
As for the other point:
The 'b' versions of nVidia's cores, G92->G92b and GT200->GT200b, signify a die-shrink (in this case 65nm -> 55nm).
Since TSMC is nowhere near introducing 28nm, we will not see a die shrink from AMD or nVidia anytime soon (the 6000-series was originally planned to be 28nm, but instead it was cut down to be more of a tweaked 5000-series on 40nm). So we won't be seeing any Fermi 'b' GPUs soon, at least not in this sense.