If you really need/want 22Mp and a lens to match it, you should be looking to medium format digital. The bigger sensors have several advantages and the price difference is not THAT great if you shop around. You could keep your little Canon for when you need to travel light.
I hear the older and cheaper backs cant compare to the newer ones in dynamic range, noise etc
so the price difference is actually very large
the new imacon 22mp is about $18 large
also Ive heard the fuji (for H series) and Zeiss lenses really arent much better than top of the line 35mm prime lenses