The published snow leopard benchmarks will be done on a 3.2. The 2.26 octo will be dropped they will keep the 3 options and keep it simple.
What is magical about only 3 options. Why is 4 options significantly more complicated? Especially one which probably won't get pulled all that often, but will be priced with even higher margins.
(Small upside for Apple can wait to see if there are buyers for 3.2 machines at those prices before commit to it. Lots of companies are not buying anything these days. The minimal 2.93 machine is close to $6K. Does Apple really need the pub of a $6+K workstation right now. The 17" laptop has already been spun into a effective "Apple is expensive" commercial. )
The only real question i still have is when will the mac pro have 12 ram slots ? This i think involves a larger case as they would have done it last time if possible.
Not until a new MacPro case design which likely means serveral years... at which point it wouldn't matter. (since the memory density would have dropped).
12 slots run counter to the objective that Apple has for their "pop out" CPU/Memory tray. (http://www.apple.com/macpro/design.html#memory)
By making the tray perpendicular to the rest of the motherboard they are constrained in width by the width of the MacPro case. There is no room for 12 slots on that tray.
Maybe on the single CPU tray. But that also means a different design approach. Apple did 1 DIMM / controller approach ( and a mode where one of the controllers does 2 if fill all 4 slots). The 12 DIMMs in the dual CPU package setup means each of the three controller has two DIMMs. So perhaps could do 6 on the Single CPU tray.
Once 4GB DIMMS drop in price won't be as big of a deal. Folks are using 12 to go "large" with only affordable 2GB increments.