Modlite has you covered and is the newest industry hotness! They have hand held and rifle bodies available for 18650 batteries. They've also go the single cell sized 18350 as an option with the same output and slightly less run time. I'm running them on all of my work rifles and as my go to patrol handheld. They are the bees knees!
Also, been a minute since I've been on their site. But Cory has indicated (ie no secret) that a production handheld body is in the future. And for those who prefer momentary only he also noted that the arisaka tailcaps on their website are momentary only vice the sf z68 clicky.
The handhelds they sold a few months ago were contract overruns amd sold out quickly.
The standard scout body can be used as a handheld. I believe Prime among a few others were attaching pocket clips to the mounting lugs, unsure which brand.
Any chance you (or anyone) could post a link to whichever light this is? I'm not clear from your post what light you're talking about, but it looks/sounds like it's worth checking out.
Edit - thanks in advance!