If you put Howard and Rondo together you instantly become relevant. You add in Pierce, Bass, Pietrus, Bradley, Moore, JJJ, two draft picks and some cap money to sign a couple good free agents at PF and Off guard and you're in serious contention.
Howard / Mid level exemption / Stiemsma
Free agent / Bass / JJJ
Pierce / Jeff Green
Free agent / Pietrus / Marquis
Rondo / Bradley / Moore
Off guard: CJ Miles?
Power Forward: Ilyasova - spread the floor for Howard?
* I mean not huge aquisitions at OG and PF - but you make your money with Howard, Rondo and Pierce...
I also think that if, by some very slight chance, Howard comes to Boston, the combo of he and Rondo will make Boston a free agent magnet, much like the big three did.
Guys will be lining up to play with Howard, Pierce and Rondo, Howard has to know this.