Come on, you don't see it happening ever? Think outside the box a little. Clearly off-camera flash is not a very big issue for camera users in general, but for advanced amateurs and pros, it most likely is. So the market is developing around 3rd party solutions right now. I am sure Canon has taken note of this.
Do you really think some issues with radio frequency regulations are going to stop them from getting this feature implemented. Even if it is just an add-on module and all new speedlites will include a radio receiver for this. But i have a feeling this option will eventually be included in the camera body. This would be such a great feature to have.
But if most of your flash usage is indoors at close range (less than approx. 90 feet) then you should really look into the Yongnuo st-e2. It is basically a clone of Canon's ST-E2, but costs less than half the price. If you have a group of speedlites, this is a great temporary solution (until radio is in-body). I have the Yongnuo ST-E2, Yongnuo 565ex flash and a Canon 430 EX ii flash. Everything works together flawlessly even on my ancient Rebel XS body. If you have a more modern body, it may work even better (you may have more flash options on your flash menu than me). But it is actually a very capable system for me. It has ratios, supports ettl ii flashes, manual mode (have to adjust at the flash, but can still trigger it) - overall a great value for a little over a hundred bucks.