Jetbeam do some well priced 1/2 decent quality holsters(mtn electronics might have them) , I use the small size for s2 sized lights and the larger size (medium iirc) for keeping my c2 lights safe . The latter probably of similar size to the L4. For a bit more, Fenix do some nice holsters as well. I got mine from HKe and keep my surefire m2 inside. They come in a few different colour options as well.
When I get in I will add a couple of pics so you will get a rough idea.