Anyone else losing hope for a new 5D MkII? (R&D problem??)

I admit up front that I know nothing about how and when Canon releases cameras, but some on these forums do.. so I ask, why would Canon announce the 50D and 18-200, then withhold the announcement of the 5DII? Is that normal? Are they waiting until closer to Photokina? Or is there some massive R&D problem with the 5D replacement? Maybe Canon was swinging for the fences with their plans for the new 5DII (21MP?) and the camera got mired in engineering problems, delayed again and again (like the Airbus A380), and just isn't ready for production. This is pure speculation on my part, but why else would Canon wait soooooo long to release a new FF body when Nikon is (I suspect) taking a bite out of Canon's market share with the D700? I want to stay with Canon, but if there is no 5D replacement by Photokina I am giving up and buying a D700.

--
Chris in St. Louis