This trade, or any other trades that involve MAJOR core players (starting 5 essentially) will not happen this year, period. Now, if this was June, 2010 I would tend to think some of these could have an ounce of truth. Let's be logical here. Why would the Celtics even contemplate messing around with their core group right now?
If KG doesn't get hurt, it's a Celtics/Lakers rematch right now, simple as that. I know a lot of people love this offseason madness, but trust me, the only roster moves that you should expect happening are signing a midlevel exception player like McDyess, Sheed, Grant Hill, etc.
Maybe another lower level FA, but remember they also have to re-sign BBD and/or Powe as well. These crazy rumors give me a chuckle.