Why not a lightweight steel bike like a Cross Check or a Jamis Quest or something? With light loads a steel bike will be much more comfortable, especiallly on 28 or 32mm tires. Those examples both have eyelets for rear racks. My Quest Elite weighs 20 lbs, although better wheels would add a pound. Still, I have Easton EA70's and I'm thinking of mounting 28mm Vittoria Randonneurs and doing some light touring on it, based on some of the recent examples I've seen here.