Expirings and a pick (or two if he agreed to opt-in to his last year) for Gerald Wallace would be an interesting all-in trade.
Give the Celtics a better version of what they were going for with Jeff Green: a swing forward to alternate between power-ball on the wing with Pierce at the 2, and speed-ball with Wallace at the 4 and KG at the 5.
That would mostly recoup Portland for their investment in Wallace too.