The Mav's have the most cap room, and at the moment, they're borderline nothing. They only have 4 players under contract. Nowitzki, Marion, Carter, and Crowder. I think in the immediate, the Mav's have bigger fish to fry. Now if the Howard thing gets resolved quickly, and they lose out, then they might turn their attention to Iggy. But they have no center on the team, much less a back up center. My guess is that if they lose out on Howard, they fill out the roster with cheap players, get in the lottery, and try to make a big splash in the free agent market next year. Cuban has stated that he wants a contending team in 2014.
It may come down to just New Orleans and the Kings. I guess we'll see!