Now that's an interesting idea.
Simplest way, at first anyway, might be a 2-step crimp.
First step is a normal taper crimp.
Second step might use a roll-crimp die which has been broach cut to leave 4 or 6 pieces of the roll.
(Or maybe reverse those two steps; whichever works best.)
It's a way to try this without the cost of making a really-complicated taper-plus-roll die.
Glock rifling plus plastic sabot?
Yeah, could be a problem, I guess.
If so, worst case is need of an aftermarket G20 or G29 barrel.