Why?
If you're riding off-road, there are benefits to UST wheels: The primary one being that you can run lower pressures without concerns for pinch flats. But there's a flip side to that... If you corner too hard or sideslip an obstacle on ultra low pressure UST setups you can unseat the bead.
If you're talking about a road bike, then there's no reason to do it. UST for road is just silly.
__________________
"I feel like my world was classier before I found cyclocross."
- Mandi M.