Yeah, I really regret so many good ideas are spoiled by a very tiny, minor single fact.
Leslie had several designs. In the early models the horn was stationary, the woofer played downwards to a rotating ‘drum’ or baffle. In later designs both the horn and the drum spun around. I don’t know why you couldn’t get a Leslie tremolo sound by spinning a couple small speakers around. Technically not a Leslie, but it could provide a cool tremolo effect. You could have two speakers on one turntable or one each on two turntables. It would be a fun project.
It's the cables. 😉 You can't twist them up endlessly, you would need to have sliding contacts, which produce mechanical sound as well as electrical ones since the contact will never be perfect, it's like wiggling on a cord on a defect cable to get it to contact/sound again.