Have you ever checked out the Nathan hydration pack? Just this morning I had someone recommend it to me. He's an ultra trail runner who's tried every combination of camelback or waist pack and said this is far superior.
I think this is the one he is talking about
:
http://www.bikesomewhere.com/bikesom...404/3789/16535
It is a vest type attachement instead of a belt and is supposedly much more comfortable.