I think you can rule out all the ones that made it to the NBA. That sort of money isn't even pocket change to them.
I think you can also rule out of the Kentucky boys because you would think they would know they could much more for it by selling it to a fan.
Teague, Lamb, or Vargas jump to mind.
Other than arguably the ones from in state, these players don't view UK the way we do, and thus don't value these the way we do. They're also all very young and don't understand sentimental value the way older people do. That or this generation as a whole views money > memories which would bring the Kentucky boys back into the pool of suspects.
Any leads?