I highly doubt the Mac Pro goes the entire year without an update. Even if you base it on the infallible

rolleyes

Buyer's Guide which considers the eight core additon an update (which it wasn't) by November 13 (MMs date) that will have been 233 days since the last one. And if we go based on the release (which is more realistic IMO) that will have been about 460 days.
Not trying to argue, but you don't know any better than we do. But based on pretty strong evidence an update is imminent and will most likely come by years end.
This Rev. A stuff is annoying. The original Mac Pro hasn't changed at all. There is no evidence to suggest Apple has changed the Mac Pro is a way that shows it was improved. Other than SMC updates.
Whats more, the original Mac Pro had basically zero issues.
In addition, what constitues Rev. A? A chassis change? A motherboard change? A processor change?
I don't see people not buying up the MBP because it went Santa Rosa. This Rev. A myth needs to die. Seriously. There isn't much evidence to suggest that every "Rev. A" product is going to have major issues.
I will also add this, a Workstation does not have to go through the amount of engineering a notebook or iMac does, heck even the Mac Mini. They are looking to make the Mac Pro thinner or lighter. Thus, the chances of having major issues is significantly decreased right there.