just a thought, ever think of your favorite sheath/kydex maker? they could be custom made for your cuffs, open at the top, with a simple strap to lock them in and to keep them from falling out,
but with a simple unhook, easy to remove and use (for them bad girls!) and with a loop or small tek-loc, low profile and attached to your belt or leg or even arm. I would guess not to expensive being kydex. just an idea.