Small update. :). Very small.
Didn’t really like the clip. Doesn’t stay in the slot well enough. Went back to the old convoy clip.
Can you provide more details on the grinding bit? It’s needed to get the head to seat onto the battery tube properly. The threaded section rests on the ledge of the battery tube at the base of the threads.
Ah. Never mind. I found that my dremel kit had the right cylindrical grinding bits and a buffing bit I used to grind out a few mm of threads. The head seats properly now and I can use the proper O-ring.
Note, I didn’t need to touch the battery tube, after grinding out the threads everything fits. I can even take a bit more off but will stop for now (107mm).
There’s a lot of space to be gained in the tail too.
Unfortunately the coloured S2+ has a fairly tall button assembly, but with a black or grey S2+ you can do several things to gain space.
I had a look, and you could basically skip the whole battery tube for a 18350 triple light.
You would then need a tall piece of threaded tube to join both.
That would be insane! A bit too short for me but a cool idea.
Careful you don’t go too far… 
Is that what i think it is on your picture CRX?
A convoy S2 head?
The last image looks a bit concerning to me, or is it just a ‘feature’?
Edit
My bad, should have looked better, i was thinking that youve burnt the led.
Probably too late for me by now, should catch some sleep :person_facepalming:
Not sure what you mean, the red light, it’s a locator light.
Does shortening the pill affect thermals?
Yep. With a pill that short it won’t handle heat as well. Should be fine to 3A or so, especially with H17F driver.
Here’s some updated pix.
Short body, updated clip. Note, the gap is gone now.
Here’s the finished product with gap fixed. 107mm.
Nice work Gunga!
Did you use a lathe or just a lot of filing?
I love to see what people achieve with just their hands, i am to afraid to destroy one of my S2+ ’es, maybe someday when i am brave enough 
Even if you’re not an artist with a file as OL was you can still have fun with a hack saw and file and you won’t know until you try how it will turn out.
I used a combination of dremel tool with cutting and grinding bits, Normal and diamond file and 320-2000 grit sandpaper.
Good job on that flashlight :+1:
I wish to have skils like that
They don’t come by themselves, so be brave and learn yourself some skills, nothing gives more satisfaction when you get the result you’d never imagine you’d could do it and reach that result
You are right Yokiamy, I’m learning slowly :+1:
I try to forget the things that didn’t work out that well, which is the drawback as this sometimes occurs as well, (which is difficult as it keeps nagging me sometimes, i always tend to think ’ what if…. ’)