Jos,
You may like the Crocodile Dundee type of rig, but unless you are standing still and facing somoene, you will never conceal a big knife this way. Any movement, turning, stretching, or sitting will cause a knife down and across your back to print. Now that you are done using your big knife, how are you going to get it back in to the sheath without sticking or cutting yourself? Looks good in the movies (fantasyland), but doesn't work in the street. The stud style sheath advocated by Bill Bagwell is an old time carry that works extremely well today. Emanuel pretty well understands how it's done. You have to find your "Sweet Spot", which will be along your torso either strongside or offside, depending on how you want to draw, and at a height that will allow you to sit without the knife kicking out the back and printing. A little experimentation goes a long way. I make a sheath (the Southern Comfort) that works just like the ones Bill Bagwell makes, and actually has his approval and recommendation. A Bagwell Bowie comes with a traditional leather sheath with the stud on it, but a lot of his customers who actually "go in harm's way" (as he puts it), will carry it in one of my Southern Comforts. Working on one now that was sent to me last week. I'm 5'9", 160lbs, and routinely carry a Hell's Belle, with 10.75" blade, concealed in shorts and a t-shirt with no problems. It's easier than you think.
