This is a modest 7% price cut, and the first one on a model that is a bit more than a year old. This is amazingly late for a first price cut given the "price aging" suffered by all things electronic, and looks fairly normal, given developments like the $2000 Sony A850 and the Nikon D700 costing less than it did when the 5DII was new. To me this is no sign of clearing out stocks for a new model, and I doubt the 5D series will be updated faster than every 2 1/2 to 3 years, going on Canon's record.
Actually, I have been a bit surprised how little the announcement of the $2000 A850 has affected the pricing of the 5DII and D700. It seems that Sony is still not taking many customers away from Canon and Nikon in this market segment, since neither those camera makers nor their retailers have shown much need to respond with price cuts.