Well...I have been talking about it for a while now, but I've made quite a bit of progress this week.
I'm building a very small triple XP-G R5 helmet mount light with Carlco optics. The driver, emitters, and optics are all integrated for a super-compact setup. Basically just provide your own custom housing and go.
I started with a piece of 1" hex bar cut to 2":
I don't have any machine tools, so I had to be creative. I had a machine shop bore the flat-bottom hole to mount the PCB to. I needed a 20mm x 11mm hole. This was the only "precision" thing that I couldn't do with my wobbly drill press and dremel
PCB with optics - 8mm
20mm lens from flashlightlens.com - 1.84mm
GITD O-Ring - 1.5mm uncompressed
I then cut a face cap out of a sheet of aluminum "freehand" with a 19mm hole to fit on top and hold it all together. I now have a lip to retain the guts. It will compress the O-ring down and should in theory seal everything off.
Here's the project pic's so far: