Dallas does this assuming it will sign Dwight.
Dallas in - Smith (S&T - 1st yr ~13.7 million), Bass (6.75)
Dallas out - Marion (9.3), Carter (3.18), Crowder (978k), Larkin (1.3), Ledo (500k), James (500k), Akognan (500k), future 1st, 3 million
Boston in - Teague (S&T - 1st yr. ~10 million), Marion, Ledo, Crowder
Boston out - Bass, Rondo, Lee
Atlanta in - Rondo, Lee, Larkin, James, Akognan, Carter, Dal 1st, 3 million cash
Atlanta out - Smith, Teague
If my math is correct, Dallas can make the trade without cap space, so their cap space can be used to sign Dwight. They would need to convince Smith to start his contract at right around or just below 14 million, but with raises it will still be a nice pay day and he can go to Dallas to play with Dwight (and the no state tax should help with the cost). Boston unloads both Bass and Lee and while Teague isn't as good as Rondo he is a nice young starting PG to build around and gets a couple of young propects in Crowder and Ledo to look at along with Marion's good sized expiring contract and veteran leadership. Atlanta gets a better PG to replace Teague, a nice PG prospect to build for the future, some young players they can keep or waive (with Dallas' cash), a future first, and depth at the wing with Lee and Carter (and since Smith is gone anyway, it is a pretty decent haul for them).