I'm in the process of building the opposite: a Tele neck on a Strat body. I bought a mexican Fender body and a Mighty Mite Tele neck on Ebay and I'm sanding the body down to bare wood right now but before that I checked the neck/body joint and nothing stroke my eyes, it fits.There's a small hump at the bottom of the neck pocket but some sanding will do the trick, it would fit pretty good even without the sanding anyway.
Could be an other story with different parts...
Actually, the guitar I'm building is a tribute to Tommy Bolin who used to play on that kind of mongrel Strat especially during his Energy and James Gang days:
And the same guitar in full: