The Mavs currently have five quality players on the team (Calderon, Monta, Vince, Marion, and Dirk) but not much else. They actually seem like they could be competitive with some depth.
Wouldn't some combination of Humphries and/or Bass and/or Lee work pretty well on their roster? They have cap space so the Celtics could basically shed a salary like Bass's (who's played there before) for spare change(2nd round pick, etc.). And the Mavs salaries after next year get even lower so they might not even be averse to taking on some contracts(Wallace? Okay, I'm pushing it there...).
It just seems like the Celtics need to shed players/salary while the Mavs have cap space and could be competitive with more depth. Looks like a match to me.