Just playing around with knife placement a little, and had a question for the experienced. It seems to me, that a horizontal knife sheath, mounted near the front of the belt, might be very ergonomic. I prefer my knife mounted in front, if on a belt, but that is obviously unfavorable for bending forward.
So I played around by just taping a knife horizontally on a belt, and found it very easy to access with either hand. On the downside, it must be positioned so as not to interfere with speedy operation of the belt buckle. Any downside to rotating the belt slightly and positioning the belt buckle slightly off center? You would want to position the sheath so that in drawing the knife, you would not inadvertently release the buckle, if using a quick release style.
I have never seen a knife sheath manufactured to be mounted that way, but it wouldn't be that hard to do. Just late night ramblings, but still curious to hear your thoughts.