The person the Celtics should make a run at is Marvin Williams of Atlanta. I know - he is a restricted free agent. However, the economy is tough, and Atlanta has others it needs to focus on financially (e.g., Josh Smith, Al Horford, Joe Johnson) and Childress might be making a return.
Why this makes sense for Cs:
1) Prepares Celtics for next seasons and next 10 seasons (Perk, Rondo, & Williams could be next Big 3 for many years)
2) Extends life of Ray and Paul (Ray to bench, Paul to 2 guard and easier defensive assignments)
3) Finally gets someone to guard Lebron and R. Lewis (Williams is appropriate size and athleticism to guard Lebron & Lewis)
4) With one players, we become a top-notch athletic team (Williams, Rondo, Garnett)
With this move, Celtics can then move spare parts to bolster bench.