I think you can just buy whatever road bike you want to ride unloaded, and then add a rack. There is a rack solution that will work on any road bike -- see my old post here:

http://www.bikeforums.net/showthread...22247#poststop

This works just fine. I think the only thing you will need to look for in your road bike is low enough gearing and sturdy wheels. I used this rig for a 4-day mountain tour in Colorado, carrying about 10 pounds of stuff, on my regular road bike which has a triple and very low spoke count wheels. Remember, if you only add 20 pounds, you just have to have wheels strong enough for a person weighing 20 pounds more than you - no big deal unless you are a larger person to begin with. You also might have an issue with your heels striking the panniers, (esp. if you have big feet, i don't) but if you use a small front pannier in back, it will probably be ok.

I'll definitely use this setup again, it worked great for me for a CC tour.