I think Bradley/Olynyk plus Wallaces contract could get us a max player in a sign and trade this summer. Might have to throw in a couple of good first rounders.
Can Butler be that guy? Maybe the Bulls cap situation makes them at least think about it. Can we pull it off without giving up Smart?
Boston would certainly have to pay through the nose, but you don't get star players very often.
In terms of salary matching, Wallace-Olynyk will be enough for most players, and Pressey can be added as non-guaranteed filler if need be. Bradley only is included if he's wanted by the other team (which does make some sense in a Butler trade, but not in other trades necessarily). Also, the Celtics will have room to sign at least one max outright with cap room, and can use a sign-and-trade to acquire a second max player. This strengthens their negotiating position, because one team will get compensation for their player, while the other team won't, and whomever takes less will get something. Furthermore, if they just trade Wallace and draft compensation to a team with cap room they'll most likely have the ability to sign two maxes outright, which further increases leverage. (Of course, this requires the C's to get two max players to agree to come here, but if so, they'll have some negotiating strength.)
The real fun happens if the C's trade Bradley and Turner before next season, because then the C's will have room for two maxes outright, and can use Wallace-Olynyk/Sullinger-Pressey to sign-and-trade for a third.