I've got a list together based on eliminating the following:
Our playoff rivals are not going to help us.
Contenders are not going to trade us good players that they need.
EDIT: also this list is based on targeting a SF/wing or combo 1/2
Cleveland: Delonte West (4.7) and Moon (3.0) for Sheed and a 2nd
Detroit: Prince (10.3) for Sheed and a first (plus Gaffney or Lafeyette)
Houston: Battier, Ariza or Jefferies (all about 7 mill) for Sheed and a 1st -> Houston is probably only mocing these guys for a solid bench center, so a 3rd team would need to get involved.
New Orleans: Posey (6.5) plus they give us a 1st rounder or a prospect for Sheed
Philly: Kapono (6.6) or Nocioni (6.

for Sheed
Phoenix: Barbosa (7.1) for Sheed and a 1st or 2nd
---> or swing for the fences with Richardson by including Davis
Portland: Andre Miller (7.2) and Fernandez (1.2) for Sheed, a 1st and a signed Nate Robinson
Sacramento: Udrih (6.7), Garcia (5.5) and Landry (or Thompson) for Sheed and Davis and Lafayette/Gaffney
otherwise we're looking for sign and trades where I don't see the incentive for an opponent to take on the buyout cap hit in return for helping Boston. I guess a 1st rounder could be worth it for the right team.
I have a feeling the rest of the moves are going to unwrap very slowly over the course of the summer.