The LeBron-Wemby duo would be interesting, but I think a trade to the Spurs is unpromising for LeBron since the Spurs are underdogs right now.
But on the other hand, a trade to the Mavs does make sense. With LeBron, their roster would seem very strong and competitive, at least on paper.
I think really only 2 destinations make sense for LBJ, Cleveland because of his home state and the upper mentioned Mavs. 2 of his close buddies and ex teammates are in Dallas so it would be a nice farewell tour being surrounded by 2 guys he won each a championship with. If it will happen, who knows. Money wise I don't think the Mavs have the financial possibilities with all the aprons in sight. Only chance would be lebron taking a HUGE pay cut, which with his inflated ego is unlikely to happen. He thinks he is still a top 10 player in this league and expects to be accordingly.