For a defensive strobe I recommend 18hz, there was a large study on the subject on CPF a few years ago and in my personal testing with pukelight my findings were consistent with that, 18hz is without a doubt the most effective non-variable strobe frequency.
Having said that a randomized strobe is better…
When you find the body I can provide the driver for it (in whatever size you need).
Right now its looking like a elzetta b134. Still hoping for someone to suggest something with a slightly larger head. May have a local engineering firm duplicate the internal dimensions of the head out of a steel blank with a 5mm thick walls.
How hard is it to make a single mode that flicks between 16 and 20 hz ?
.would 17 to 19hz be better? I did read the cpf post and a few other articles. Would be interested in knowing what a peakbeam maxabeam varies between in strobe mode.
Just 16 and 20? Sure.
Are you against fully randomized (but within a set min and max Hz range)?
Like I said I recommend 18Hz, I absolutely would not go any over 21hz, any faster than that and in my personal testing (I have devised a very good strobe effectiveness test but thats a story for a different thread) you may as well be shining constant light at them, its to fast to be effective at all. *
*Note once you get above 100Hz it starts to work again on the principal that it gives you an almost instant pounding headache but it gives the handler (the one using the light) the same headache, it doesnt actually work the same as an 18Hz strobe at all to hide motion.
quick overview of my testing method-
handler (guy with light) : perp (bad guy)
get a t-ball T that can be set to about 1m height
Place tennis ball on T 18 inches from perp (WITHIN arms reach)
Handler stands 2m on other side of T (both facing eachother with T in the middle but closer to perp)
Handler strobes perp and within 5-10 seconds (randomly choosen) lunges at perp trying to knock ball down, perp tries to detect movement and knock ball down first.
winner is who knocks ball off, all the perp has to do it swing his arm out and knock the ball down, handler has to close a body length gap. in my testing well over 90% of the time (in a fully dark environment) pukelight allows the handler to “win” (and about 70% of the time with medium to high ambient lighting). I have done no testing with white only.
What this test shows is wether or not the handle would be able to use the strobe to hide his impending take down (or get away from) from the perp, if handle “wins” that means he would of been able to take down the perp without the perp even being able to pick up his movement to defend.
No objections to constantly vairable 16 to 20. I haven’t looked into modding far enough to know which is easier to do.
Figured having 2 set freqs and having it flick between them would be easier.
Dont want to go below 16 due to stop motion effects… or above 20 due to lack of effects….
A set 18 is my 2nd choice.
Sounds like my old Tigerlight FBOP would be the perfect host for this one…
Lol. Finding lights that exist still is a benifit 
Going off what hereagain just said OP I would recommend you get a pukelight from me, I would gladly sell you the TK45 proto (fully developed UI but I switched the production version to using an EA41 as a host).
It’s got plenty of mass, a nice strike bezel (but not overly aggressive) and since it runs on AA/NiMH there’s no danger of overheating cells in the hot car. It also has single button single click direct access to the main stunner strobe function (a randomized frequency randomized RGB firing order strobe designed specifically to disorient) for self defense and I could turn off all other modes for you (tho you may find the police strobe useful too).
It’s quite expensive (I would only charge you $10 over the exact parts cost since it’s just sitting on a shelf) but it is EXACTLY what your asking for, literally every spec you listed describe it to the T.
Smooth head… fairly thin body… tk45 ?
Are there 2x tk45 ? The one i see has a thick 8 cell body and a lumpy looking 3 led head…
Do explain driver further?
I haven’t done nearly enough research on drivers.
Would it be possible to do a standard variable strobe as primary then add a hidden med/low mode?
I dont want to risk hitting wrong mode is all.
Would rather have no extras than that.