Jamie,
I can see two obstacles to consider:
1: The intake plenum is very near the exhaust manifold, so the amount of water in the system would need to be large to soak up that heat and not super heat the water
2: The air in teh intake doesn't hang around for very long (before getting sucked into the cylinders), not long enough, I would think, to shed much of it's heat.
Does that sound right?
Tim