I don't know that we have a realistic shot at trading for Prince. But Sheed, I think is a possibility that's worth exploring. A smart veteran that gives us length, outside shooting, toughness, rebounding, post defense and offense. He's pretty close with KG. The only question is his asking price and whether or not he'd take a backup role. Although even with a backup role he'd still get a good 30min a game. Wallace is my first choice to add for this off-season.
My wing would be Matt Barnes. He's a tough veteran shooter with some athleticism and can finish at the rim. At point, I'm not sure what is really out there though.