Hiya Gont,
Welcome to the Busse Madness!!! I concur with the recommendations that Eric made. Those are all very high-quality makers of sheaths.
Given your specs for the sheath, allow me to add Robert Humelbaugh over at Survival Sheath Systems to the list of sheath makers whose work you should consider.
http://www.survivalsheath.com
The reasons I think his work may work for you are:
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1. He regularly works with non-standard carry options. His website shows a few of his "not just for your belt" sheaths. LBE carry should be a piece of cake for him to do.
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2. He is an ex-military groundpounder of some sort IIRC. So he's spent his fair share of time humping around under LBE and knows whereof he speaks when talking about what should (or not) work for military operations.
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3. He lives within about 20 minutes of Ft Lewis and about 40 minutes from Tactical Tailor. Let's just say that he lives in a "target rich environment" for developing emminently practical designs with some of the best testers on earth handy to his back door.

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4. Given my dealings with him on a special custom rig I had him make, IMHO he'd do what is needed to insure that any rig he made for you would fit on a TT LBE setup the way you wanted or would make it right if it didn't.
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Some of his postings here on BFC (Robert H) may seem a bit flip at times, but he is one of the people I'd want to see covering my six when the chips are down.
Thx for the bandwidth, -- Greg --