The latest rumor I've heard/seen is that Canon might announce 1Ds MkIV in August... Which is about a year overdue.
I've heard/read no mention of a timetable for 5D MkIII, but both the 5D classic and 5DII were rolled out about one year after their respective 1Ds models. Some think Canon did this deliberately, so that the 5D model would have minimal impact on sale of 1Ds models.
If the above holds true, then we might expect a 5D MkIII to be announced August, 2012.
But there are no rules anywhere that say Canon has to do their introductions in this sequence or on any particular schedule. All this is rumors and speculation. Canon could announce a 5DIII tomorrow... or never.
When and if Canon does announce a 5DIII, the 5DII will start to drop in price over time. You can probably expect them to hit $1500 a year or two after the III is announced... So be prepared to buy in, say, August 2013 or August 2014.
While I agree that lenses are far more important than the camera you choose, don't be an L-coholic. There are lots of great lenses that don't have a red stripe on them.
You do realize don't you that a modern T1i or T2i or 50D would completely blow away your 1D for IQ and allow you to continue using the crop lenses.