The engines are impossible to find anywhere. All of them have been snatched up already for the second gear shaft. Everyone in the UK hates these motors, and they've all been junked or stripped for parts.
There is a Sachs model, but it's slower.
I have a Minarelli P4 and two P6's, and I think I can make one fit by just drilling another hole for the motor mount.
The chain is on the other side on the Minarellis, but I can flip flop the wheel, weld a brake tab, and redo the rear foot brake.
In my head it seems pretty easy, but I won't know till I try to mock it up.
As far as unloading it onto someone else, I want it, and it can't be fixed without new gears and a shaft, so unless someone can machine gears, or has a hidden stockpile of obscure JLO motors, it's useless.