Just did the 650b conversion this summer. I tried to read as much as I could about the conversion but finally decided I just had to take the plunge and see how it worked out. Had the LBS build up an older mixed set of hubs (White rear (disc), Hope front) with Velocity Cliffhanger rims. With Panaracer Col de la Vie 650b x 38's (actually 584-40) they just fit our Erickson. Went to disc brake rear but rim brake front to avoid the need for a new fork. Had to replace the front caliper with a long reach but it works well. Quite pleased overall, and have had some great gravel grinding rides - rail-trails, dirt roads, etc. The one issue is that the Erickson has quite low bottom brackets to start with and the overall 1cm drop compared to the 700/28s is quite noticeable, especially since the point for us is to get off pavement. We both love the cushy ride, and getting away from traffic.