Personally, I think that carving a hole in the back when you can stick a nice bigsby on the front is sheer madness!
Also, while it'll sound a bit ballsier and more telecasterish, it won't sound 100% like a telecaster. So much of a tele's tone is down to the simple bare bones construction and the unique bridge. It's to do with the coupling and the break angle I'm told, that and the lack of a gaping big hole in the back! :P
But it sounds like a really awesome idea either way, and that Avenger guitar looks awesome!