I made an attempt at this. I pulled Portland into the mix because of the reports that David Lee would be a good match for them to help with their salary floor problem.
Boston receives: Horford, Mack, Connaughton
Atlanta receives: Sullinger, Rozier, Dallas 2016 1st, Philly 2016 2nd
Portland receives: Lee, future 2nd round pick
http://espn.go.com/nba/tradeMachine?tradeId=zpppls7Why for Boston: They get an All-Star small ball center who can pass, hit the 3, and handle the ball. Mack is a Butler guy and would be depth at the guard position. Connaughton is a MA native who can either be waived or sent to Maine.
Why for Atlanta: If they do in fact want to hit the reset button, this would be paired with a Teague trade. They get a young rookie PG to play behind Schroder and the bird rights to a young PF in Sullinger. Add 2 picks, one being IMO the very valuable 31st pick. They clear off Mack's last year and make space behind Schroder for Rozier.
Why for Portland: They bring their salary up to the floor and don't have to pay the penalty. They get a future second round draft pick out of it.
We could also get super ridiculous with a 4 team trade
http://espn.go.com/nba/tradeMachine?tradeId=jx6deje