I've worn my LMF II horizontal. I just laced a webbing strap through the top and bottom loops of the sheath (minus the MOLLE stuff) and then worn the strap like a belt...I usually strap it to gear but if I'm not carrying a pack, this is where it goes.

Sometimes I wear it like that to keep things low key. When I'm camping with a bunch of 'leave no trace' types (my wife and I call them 'tidy campers'), having a big tactical knife on the outside of my pack just generates too many questions and concerns...I guess they're worried I'm going to go John Rambo on them...or worse a tree.