>I don't think I've seen one with a rosewood neck before.
Good observation ! I think all original thinlines came with maple necks. But since I didnt like the (polyester lacquered) maple neck, I just put a 69 rosewood neck on it. The maple neck of course I keep in the case if I ever want to sell it. In 2045 or so.
The one on the far right is a 66 so it still had a nitro lacquered board which is fine too. But I cannot understand people liking maple neck teles or strats from the late sixties and seventies. Those feel horrible like you are holding a plastic neck in stead of wood. The new polyurethane necks are fine too.
The one on the far left is a factory bigsby tele model so no holes on the back. I wouldnt say it gets more sustain but it definately takes away the twang. If you dont like the highs in your tele you perhaps should look into better pickups or pickup adjustment. But IMHO bright twangy sound is just what tele's are all about.
if you just had one guitar I can imagine modding it to be more versatile. But if you have a gretsch with humbuckers and vibrato anyway ; is is not more fun to have a hard tail single coil tele as well ? Two very fine guitars each with their own distinct sound.