Depending on your budget, there are tons of vintage touring bikes out there still. Most of them are good candidates. I tend to look at tubesets so I have some kind of idea of how the bike is going to ride. This one is Tange Champion, basically a Miyata 1000 rebranded, so I couldn't pass it up.
lovely bike, I would love a frame like this to build a commuter/touring bike but have no idea what to look for.