Well, I play a lot with heavy bendings and prefer locking tuners. I replaced the original tuners with Schaller M6 Clamped 3R/3L Chrome2. Fits and stay in tune. For warranty repairing by Line6 I had to replace back to the original tuners and it was easy.
However, I am not allowed to use the picture links in this board, so here is the link to a post in the German line6forum.com with two pictures of my JTV-59 TSB and the Schaller M6 Clamped 3R/3L Chrome2: http://line6forum.com/viewtopic.php?f=76&t=11783