This discussion sounds a lot like a "Tim the-tool-man" type of rationale for having the biggest available tool. I have the EOS Digital Reel XTi with a BG-E3 battery grip and it feels like an ample handful of camera to me. I have big manly-man hands (wedding ring size 12) and able to wrap my hands around a football or basketball (well, not really around, but enough to hold with one hand) and I do not think of the camera as being too tiny to comfortably hold. I will concede that the kit lens, while being a very fine lens for the price, is a bit small for cradling the lens in the left hand, especially for big hands. Since recently getting the EF 24-70mm f/2.8L USM lens, it stays on my camera most of the time and leaves nothing to be desired from the perspective of ergonomics (not to mention IQ). I tried out other Canon models in my local camera store (Arlington Camera) while looking at various lenses and didn't see any show-stopping ergonomic differences between the various models.
The only complaint that I have about the XTi (and this applies to all of the other models as well) is the lack of good tactile buttons. This is probably just a personal problem related to my lack of good tactile sensation in my fingertips caused by MS, but I am reasonably certain that I am not the only one who does not like all of the tiny buttons and wheels that do not have well defined edges to distinguish them from their surroundings. If anyone knows of a service that performs button modifications, I would be interested.