I'd like to see Crowder, but more for a couple 2nd rounders and or Ibaka. He would fit well, but hasn't played all year and at this point with just over 30 games left not sure I'd give up anyone that actually plays.
I can see Gordon, but would only want to part with 2nd rounder and maybe Nwora or something like that. Guy is getting up there and is a rental too.

I think Allen will be really key off the bench once Middleton is back in the flow, so I'd hate to give him up for an unknown fit on the team.