My basic rule is before I sell a keeper bike, I have to have a "better" replacement in hand. One comes in, one goes out. This has worked pretty well for me and the keeper fleet is continually upgraded.

Touring mixtes are hard to find. That was a sweet bike. If you don't need a mixte style, I would just start looking for an equivalent or better replacement. I have a Miyata 215ST in my keeper fleet right now. Got it off ebay last spring at a reasonable/affordable price.

+1 The only sellers remorse I have is for letting some nice bikes go too cheap. Its just part of the learning process.