I haven't crunched the numbers, but I think if Dallas sent out Vince Carter in such a deal, it could work. How ironic would it be to send Carter back to Toronto?
Dallas trades Vince Carter and Jason Terry (S&T), receives Jose Calderon
Boston trades JaJuan Johnson, Sean Williams, E'Twaun Moore, receives Jason Terry
Toronto trades Jose Calderon, receives Vince Carter, JaJuan Johnson, Sean Williams, and E'Twaun Moore.
I suspect Toronto would also get some cash, from Boston and/or Dallas, to cover some salaries. Of the players the Raptors would receive, only Johnson's contract is fully guaranteed; the others could be cut for some payroll savings/cap space.