I see Bosh going to the Rockets in a package like:
Houston sends Scola, Landry, Lowry and McGrady
Toronto sends Bosh, Calderon, Johnson.
Toronto could then buy out McGrady at a savings, pick up Landry's option for next year, and audition Scola and Lowry to see if they are worthy of extending. If they are they can do so, if not they have sign and trade options on them or they can renounce them and some others and have some decent cap room.
Houston is like the only team in the league willing to give up talent for Bosh without a guarantee to extend him immediately. I think something along these lines could work for both teams.