Well, it's kinda you-against-the-world condition here (scratch head)... I'm not laughing, just curious: why would you prefer trackball mouse?
As for the answer, I honestly have no idea. Input devices' manufacturers have left the trackball design years ago. Even if you do manage find it, it will be most likely an old stock item, which makes the quality compromised due to aging factor.
As for the precision issue, since the trackball technology already reached its limit, the precision should be uniformed. That is assuming the mouse is made by a reputable manufacturer.
Interesting issue though, I'll see what I can find.
Do you know of any good keyboard and trackpad combos that may be better than a trackball? I am open to suggestion. I like a mouse and have some very high-end ones, but they bother my hand and wrist.