I had a similar idea:
Garnett to LAC for Odom and Bledsoe
Pierce and Barbosa to GSW for Barnes-Thompson-Jefferson
The LAC seems reasonable to me -- they were willing to part with Butler instead of Odom, but it's not a big stretch to go from one to the other.
The problem is with GSW -- if they get Pierce, it's very difficult to work out any salary that matches. Jefferson makes sense salary-wise, and Barnes makes sense talent wise, but that deal doesn't work with contracts. So that necessitate Thompson coming over, but now that makes no sense if Golden State is trying to win, so they get Barbosa.
The issue is I'm not certain it makes Golden State any better than when they started. It does clear them of Jefferson's terrible contract, and if they choose not to keep Pierce, or if Pierce retires opts out (see discussion on the front page as to whether or not he can opt out) they clear a lot from their books next year, which has some value. I'm not sure it has enough value to warrant trading Barnes and Thompson for half-year rentals, however. Which would mean they'd keep Pierce, and save a little under a million, and then be without Barnes and Thompson. The moral of the story is that it's tough to make a deal with Golden State which makes sense for both teams and works with the salaries.
However, in my above hypothetical situation, I also propose trading Terry and Bass to Milwaukee for Beno Udrih in a pure salary dump. Doing all this and waiving Jefferson with the stretch provision (assuming I figured out how that worked correctly) next offseason could leave us with a nice young core and enough cap room to go after free agents with more than the MLE.