Melo and Harrington
for
Allen, Davis, JO, Bradley/Erden, 1st this year, protected 1st down the road
I don't think Denver would do this as I think they could get a better offer elsewhere, but in theory would the Celtics entertain the notion of renting Carmelo with the hope that he might sign the extension once he gets here (obviously you don't mess with chemistry of this team for a one year rental unless you think you might have a shot at signing him long term).
I would envision the C's going small or big depending on the matchups but essentially would start Rondo, Pierce, Melo, and KG and have a floater depending on the opponent (Daniels/West or Perk/Shaq).