Given that the Pistons want to shake things up, how does this sound?

Prince and Billups
for
Marion and Banks

This works monetarily and would be great for the HEAT. It would make them instant contenders.

This would help the Pistons in that they can either have Marion for the year and resign him or let him walk and would have Marion and Wallace's contract off the books next year. They would have a ton of cap space to create a completely new roster.

What do you think?

not too shabby

 although Miami does loose some offensive firepower by giving up Marion

Really like it for the Heat. 

If Detroit were to trade two of their core pieces, they would want to get much more in return...and by trading two players of their core that would also mean they were rebuilding and would want young, talented prospects in return, which the Heat do not have, or draft picks, which would not be good because the Heat would then make the playoffs.