Going down a slightly different route, you could probably mod a second hand Telesonic. I can't be sure, but I reckon those DeArmond pickups aren't a million miles away from P-90's in size.
It's six of one, half dozen of the other, really, between it and the Tele' Junior. The bolt on neck might give you more of a Tele' feel, but then the switching's all wrong, and neither has a particularly Tele' bridge. Ah, decisions, decisions