Kelley Customs also does awesome leather Becker sheaths, in a little bit different style from Skystorm.
I was going to recommend tommythewho for wood, as well. And TKC for G10 - except I don't see any for the tweeners (16). I have yet to buy any because I've been making my own mycarta scales for my 24, 7 and 16, but they come highly recommended and look great.
Factory micarta looks like a great way to go, and a lot less work than doing it your darn self!
It's fair to note that you are certainly welcome to glue (or epoxy) your scales on, but one of the nice things about the Beckers is they are secured with fairly standard hardware. (Looks like both Tommy and TKC include slightly different replacement fasteners with the scales.)
If you glue 'em on, you're going to have a heck of a time removing and reselling if you decide to try one of the other materials.
I just put a dab of blue loctite on each handle screw. I can take 'em apart when I want, but they're very unlikely to come loose on their own. (Haven't on me, even with some battoning.)