Isn't this similar to the "taser" ignitor internals? What is the differance?
Although this is probably a bit off topic, I never could resist telling folk how (I think) things work
Generally tasers - and I'm assuming these taser "modules" - work by charging a high voltage capacitor up, and discharging it through a cheap potted transformer. Potted because its secondary can develop well over 50kV, can even be 100kV if the insulation holds. And cheap because its primary only has a few turns, and its core is just a block of laminated iron. There are two stages involved, no voltage multipliers although I guess they could use one or two stages.
So first the input voltage is stepped up to 400-1kV to charge a -0.5-3uF cap. This is usually done with a flyback converter as that's the most efficient way to step up voltage and charge a cap (since its a current source). It is charged via the primary of the second transformer, and there is a spark gap that, when the cap reaches its target voltage shorts across the cap and primary, effectively dumping the caps energy into the second transformer. So it gets stepped up again.
The upshot is, its output is far from DC. Its low duty high power, high voltage. So brief millisecond pulses, at several hertz, and possibly at hundreds of watts per pulse (but low average power of 10W). It makes then great for sparkers and to cause muscles to contract violently to use up muscle energy stores, but pretty terrible for any kind of lab supply.
Its output pulse frequency depends on several things, input voltage (how quickly it charges the cap) humidity (which determines breakdown voltage of the spark gap) etc.. I bought a couple for novelty value, but they scare me.
There are other "kits" on ebay/amazon that aren't potted modules and just have a transistor, and a high voltage flyback transformer rated for 20W tops. They have a feedback winding that allows it to be self oscillating, so whilst you can't control the turns ratio as the transformer is made for you - you might be able to add feedback to its sort of regulated.
https://www.ebay.co.uk/itm/15KV-High-Voltage-Generator-Step-up-Transformer-Igniter-Coil-Module-DIY/282659520031that sort of thing. But at 15kV again its over kill.
For 1mA a 1kV transformer with a few multiplier stages could easily provide the required current at DC as well as at a level of safety has it is inherently limited to a few mA (so it'll sting, but won't be as dangerous). Two of us have mentioned CCFL inverters so far