joebe,
My personal preferrence for comfortable large blade carry is IWB. No confining shoulder straps and the weight seems to carry better on the waist. The sheath system Bill Bagwell uses for his knives (belt stud) is so KISS simple and easy on/off, that I'm really surprised that more large knives aren't sheathed this way. Can be carried strong side or crossdraw in an infinite number of positions and angles. I'm 5'9", 173 lbs., and can hide a Hell's Belle in shorts and t-shirt, seated, with no problems or discomfort. It takes a little experimentation to find out where it'll sit best for each individual, as far as concealment and ease of presentation goes, but well worth the time, because this is a truly comfortable way of concealing the "big boys". Bagwell's system impessed me so much (after carrying this way for a few years), that I figured out how to do them in Concealex and added 'em to the line of sheaths I do. As far as shoulder rigs go, Blade Rigger does some top shelf stuff, Matt Draper's got some very good things happening, and there is a new guy, Rob Humelbaugh, who has some great "knife amd hawk" systems.