Craig Meddaugh , Mar 11, 2012; 11:00 p.m.
Short answer, nobody knows. There will of course always be new cameras, but nobody knows anything about the specs, timing, or pricing until Canon makes an official announcement.
Unless you want to sit around waiting for a year camera-less, you have to buy whatever is available. In your case, there are a number of great cameras available,either the 7D (which is a step-up from the 50D in terms of speed, handling, and gives you an advantage in high-ISO situations) or the 5Dii which will slower in terms of AF and frame-rate, but delivers exceptional image quality.