I'm not sure what the minimum A2C is gonna be for a 29'er, but if that don't work...build a 26r / 650b front setup.
You used to be limited by tires for the 650b, but you can get a 650b Kenda Nevegal now. Build up a 650b Stans ZTR or Velocity Blunt on your hub of choice, and you should be rockin'.