My guess would be get the 5D mkII now if you need it. Canon seem to be re-vamping significantly their line-up and I fear we may not see any replacement for the 5D until well into next year . Keep in mind this red dot camera is in development, no launch date yet. Coupled with Nikon production problem which mean they are not yet able to put any pressure on Canon 5D sales with a new model yet, Canon does not yet have any urgency to replace the 5D...You can always sell your 5d mkII later if you want.
My two cents