Got the neck right here on the classfieds.
Now the question becomes going one of two routes:
1. Modding a P bass body to fit the neck and pickup.
2. Getting a B stock L2500 body for 65$ from G&L, and if the neck position is the same as the L1005, plug the bridge pup, and refinish the body. Plus source a G&L saddlelock 5 bridge (haven't seen any for sale)
The G&L body will be smaller than a Precision body, the pickup route is in the right spot, and you know the neck and bridge will fit with minimal effort. So, provided you're good with filling the pickup hole and refinishing it, that would be my recommendation.
Though some crazy Fender/G&L mashup bass would be pretty cool…