I wouldn't trade Rondo for 1st round picks from a mavs team that would then have Rondo, Howard, Nowitzky, and Josh Smith. No way! We already got plenty of picks from the KG, Pierce, and Doc trades. We don't need very late first rounders for our best asset.
I would instead wait until he comes back healthy, raises his value back to pre-injury, and then trade him possibly with a pick or two for a superstar.