Reason #3: No state income tax!
Seriously, the Mavs are in the running for Lebron if you think about it. He most likely doesn't want to screw over his home town and leave them high and dry but he doesn't want to stay either. The solution to this is pushing a sign and trade. The catch to that solution is the Cavs wouldn't trade him in the East.
James to Dallas makes sense for both parties. The Mavs have never won a championship and have always needed that superstar to complement Dirk to push them over the edge. Lebron can build a dynasty in Dallas, and if Dallas wins with Lebron, James would get the credit.
Plus, Dallas is a much nicer place to spend your time in than New York, Cleveland, Chicago, or Miami.
I say that Damp's expiring contract + Barea + Butler + Cash + 1st round picks gets it done. I'll even give up JET or Roddy.