Not really a threat to the Cs per se, but still interesting.
The Dallas Mavs, if they free themselves of all cap holds this off-season, will have approximately 32 million in cap space.
Their 3 biggest contracts are Harrison Barnes (23 million), Wes Matthews (18 million expiring), and Powell (9 million).
Harrison Barnes + #5 pick might be enough to entice a team to give up a disgruntled all-star level player. Matthews could be stretched (saving about 14 million on their cap this year) or traded to a team with cap space or non-guaranteed contracts. Powell is a useful player that could be traded as well.
Dallas is a growing city in a state with no taxes. They have an owner who has proven to be an aggressive winner and a top 8 coach in the NBA.
I still think Paul George is going to LA with Lebron James.
I think this is a highly unlikely scenario.
But let's just say the Lakers are unable or unwilling to trade for Leonard and/or sign one of George and James. With some creative trades, the Mavs could position themselves to be able to get a Big 3 of James, George, and Leonard. The rest of their team would potentially be Barea, Smith Jr., Dirk, and Kleiber, which isn't exactly a great bench.
It's just interesting how Cuban has positioned himself to always be a player in the off-season, but never is able to get the top guys.