It would be cool if he was open to signing one year contracts and reupping at the end of every season. Though I doubt the kind of cash he'll earn will be much more than a drop in the bucket for Cuban and the Dallas FO, it would be rough if they signed him for 3 years and his game fell off dramatically (to the point that he hardly even played).
Then again, they don't ask much of the guy to begin with outside of being a facilitating floor general spreading the floor and coming up big with timely perimeter shooting. It's not like he needs much in the way of speed or athleticism to do work.
Still so happy for the guy that he finally won a ring.