I posted a awhile back a late 80's Koga Miyata Valley Runner I built up as a loaded touring bike. Many Japanese bikes (Miyata , Panasonic, Fugi's - just to name few) made before the the currency conversion made it cost prohibitive to import them made great bikes for touring. Like Miyata610 states and I agree many are better made than the mid level touring bikes of today. The secret is to find a nice frame and have the patience to build it up to mechanical standards of today - or leave retro as the case maybe.
If you like to search and playing with bike parts as I do you will be rewarded with a touring bike that in many cases can not be match without expending $1,000's of dollars in todauy's dollars.