If Portland would agree, I'd absolutely do this, even with a first rounder included. I think Wallace would bump this team up into the second-tier contender bracket.
He'd be perfect for our team in terms of matching up against Miami, as we could neutralize Miami's small ball lineup by having Wallace cover Lebron. He'd make the team much better, as we'd essentially have a more talented James Posey on the roster.
Of course, I'm not sure what Portland wants, or if they'd do a deal for only one #1. However, I wouldn't worry too much about his contract; even if he opts in, it would be an easily tradeable asset.