As it turns out, TTC has just let the cat out of the bag about their new 500/600 shifter. It's made for them by Hurst.
The only reason that it doesn't include adjustable positive stops is that many people don't know how to set them properly. The rumors about them being bad for Tremecs and blowing them up has nothing to do with the stops themselves, or the inherent need for them- but rather in common incompetence. If they are set too close, it prevents the gears from fully engaging. Well, of course that will cause a problem! So basically they stupid-proofed it, and hope you won't pound it too hard. BTW, that piece of info strait from TTC, not just my opinion.