Keith, it may not be fashion concious but what about puting your camera bag inside a normal roller type piece of lugage. Have found Lowpro ruksack a lot cheaper than their camera ruksack and the bags are the same, it's just the liner that is differant. I would look at getting the next size up to that which fitted your camera bag so that you had room for waterproofs, flask and sarnies.
I was considering buying a luggage trolley case and wondering how to line the inside for added protection? The Lowepro Roller trolley cases are fine products no doubt, but they seem to be grossly over priced.