Brandon - Weight is not a significant issue, which is why I'm leaning towards cyclocross frame, vs. touring. It seems to me that touring frames are overbuilt for our needs. I mean, I'm thinking of this in UL terms: touring frames are like 80 liter, 6 pound Lowa backpacks.
As an example, the SOMA touring frame weighs almost 5lbs, whereas their CX frame is closer to 4 lbs and can come with a lighter fork. An extra pound or two does make a difference, but I agree that it's not paramount. Fit and ride quality are key, with a balance between speed and durability.
My wife weighs 130 at most, and will be carrying 10-20lbs of gear, including the rack and panniers (if necessary). So, say 160 lbs max. She would fit a 54-56cm frame. We're not doing any crazy touring in Bolivia, off-road stuff, or extreme wet climates.
However, I understand that the geometry is slightly different for the two types of frames. Are there any light steel touring frames? I checked out the BTL and it looks like a good bike, but still overbuilt for our needs.
Conversely, I could go with a SOMA Smoothie ES, which is a relaxed geometry version of their road bike. It would probably have similar geo to a touring bike. Downside is it lacks the canti brake studs.