If you have a tall enough drill press or a woodworking vise, you could clamp the body in such a way as to afford access to the jack hole and recess it slightly with an appropriate diameter Forstner bit. Drill press would of course be preferable.
I think forum member Hendrix may have attacked this another way; you might search for his threads in the work-in-progress subforum.
Finally, if you're not hung up on a traditional Tele cup jack or the more modern Electrosocket, consider a football plate or a square Les Paul-style jack plate. So much easier than trying to fiddle with a body you're aching not to screw up.
