Would it be possible to put ethylphenidate or MPA into the e-mixture of an e-shisha? And would have an effect similar to the way nicotine in the tinctures work?
I really doubt it, but have not tried it myself as I do not tolerate MPH well and have never had any desire to try EPH due to how shitty MPH makes me feel.
Also, judging doses of the drug would be an absolute nightmare-you've no way of really knowing how much you'd get per puff, and you may find yourself of having to inhale the whole cartridge if you didn't put enough ethylphenidate in there.
I've thought about doing this with other drugs, it's a good idea in theory. (I've often wondered about putting freebase codeine in an e-cig cartridge).