Seaward,
don't know how much help this will be, but I've been using a SureFire holster with my U2 - unfortunately, I don't know which one it is. Got it from a SF dealer I met at a gun show. Tried several until we found one that worked, and the packaging is long gone.
It's nylon, and has the quick-detach feature. The U2 with clip fits comfortably but snugly down in it to the base of the head, covering the adjusting ring (ca 1.25" diameter). The flap is generous, but does still have enough hook-and-loop overlap to work just fine. Generous enough to also work great with a filter mounted on the U2. There's about an inch of free space in the bottom of the holster, but that hasn't been a problem so far.
Given the length and style, it's probably either a V11 (9P) or a V31 (8AX/8NX). A G2 drops in very loosely. An 8AX/NX has the same bezel diameter as the U2, so the greatest likelihood is that it's a V31.
Maybe one of the other CPFers can verify...