I've had a couple showcase tele bodies routed for humbuckers, and you can still see part of the tele routes when it's done. The angle of the tele bridge pickup causes it to protrude past the humbucker route on the bridge side, while the tele neck pickup is wide enough to hang past the humbucker route in the corners closest to the neck. The areas where the tele routes protrude are pretty minor, though. As long as you're talking about a guitar with a pickguard, it's nothing a few minutes with a dremel couldn't fix.
-Bobbie