I wouldn't mind acquiring Lee to pick up a pick but we already have too many late firsts/seconds. If we could work out a three way deal where a team in the late teens/early 20s gets 28, the Golden State pick, and gives us their pick, that might be something I'm interested in. Maybe something like this?
GS gets our top 55 protected pick next year
We get #23, David Lee (absorbed with Rondo TPE)
Portland gets #28, #30
Golden State saves money, can re-sign Green
We move up in the draft
Portland moves down 5 slots and picks up an extra late first. This makes sense for them because their bench last year was abysmal and if they re-sign Matthews and Aldridge they'll be capped out. They also don't have a second round pick, so this is a way to add 2 bench players instead of 1. Considering that they have stars in place and are looking to round out their bench, they'd likely benefit more from that than from adding one slightly better prospect. This trade is obviously out the window if Aldridge leaves and maybe if Matthews leaves as well.
Edit: Just saw the post about trade exceptions. So even if they're within 20% of the incoming salary they can't be used? Even if they can't, we could still do this trade couldn't we, since we have cap space? Granted, we'd be punting on signing a major free agent, but if we decide we don't have a shot it's worth looking into doing something like this.