I am looking at building my mom a commuter/get around town bike. Now her last bike (like 20 years ago) was a road bike and we live in Maine with unpredictable weather, rough roads and steep hills. So I want to build her a cross bike on a budget. Nashbar has a CX frame and fork that are disk compatible. I really like Trek's Portland commuter bike with the disk setup, and this is the direction I am thinking in. I'd get Tektro's Lyra brake set, but where do I find wheels?
Oh, and I am all for disks (or hydrualic rim brakes) on road or CX bikes, but I am 6' 2' and 220 lbs. Look, just because the Mt. Bike versions of those brakes are stupid powerful doesn't mean road and CX bikes will get the same brakes, or even should. That's what engineers are for. You can play with disk diameter, master and slave cylinder size (piston size) to get the appropriate braking force, modulation, and progression for the application. I read a review once of the Portland I think, that said the 140 rotors were very reasonable to use on the bike. But that's just me.