if you get to the point of boiling water there are gonna be other serious issues that will matter more than the steam..

i remember seeing here on XS (i think) or maybe Tom's that 3M has a liquid that boils at a relatively low temp and they demonstrated a submerged overclocked system running without a heatsink at very good temps. A cookie goes to the first person to bulid a farm in a huge fish tank full of that liquid