Rolf is still in business, but I think Trek actuallowns the Rolfwheels.com domain name -- so there's the problem. I know a lot of people who swear by their Rolf Vector Pros, though.
Me? I don't like them for a 'cross bike, though I do know of people who ride them on 'cross. I just don't like low-spoke-count wheels, I guess. My preference would be for a set of wheels built up from Mavic Open Pros or MA3s for 'cross. In case you're wondering, you could have a pair of Open Pros built up with Ultegra hubs for about $300, MA3s for $250.