And I'm back to Plan A - build a KX125/KDX175 hybrid.
The KX frame has a flogged out rocker hole (and it would be a total prick to repair, as the hole is obscured by other frame tubes, and someone has had a crappy go at fixing it before now). Its also previously broken on the front down tube, and that repair is structurally sound but ugly as sin.
The KX crank is also damaged on the drive end.
Shock will probably be KDX with the KX's cannister.
So... KX forks and swing arm into the good KDX175 frame. Not sure whether to make it a 125 or a 175 though. My heart says 125, but my head points out that while Vinduros are non-competitive and have no classes, the sensible thing is to make it a 175.
I'll be keeping all of the 'left over' bits, so bth bikes can be returned to stock if someone finds the motivation to do so.