My dad has an older USFS wildfire belt & suspender kit that he is looking for. Always liked those too and will try that out.
Ugh...don't. Can't put it any more succinctly than that...just don't. Massive slippage and poor weight distribution.
Recommended: the Pack Shack's webgear (bottom only):
http://thepackshack.com/shop/agora.cgi?product=PacksNobody is going to know what's going to fit you except you, so see if you can arrange a meet-and-greet-and-fit with one of the Tonto's 'shot crews (PV, Payson, and Globe)...they might think you're nuts, but they'll probably let you hike around with one for a bit. Shot crews are down right now, so ask for the Hotshot Superintendent or the AFMO (Assistant Fire Management Officer). The Mesa RD engine crews also used them if that's closer to home (Lower Salt River Rec).
This is all ten-years-plus info, by the way. But somebody should know what you're talking about and be willing to help out.