I agree w/ BobbyB that the Japanese frames are readily available for a
good price. One approach that has worked well for me is to put a
"want to buy" ad on craigslist. For example, post an ad that says
some like "I'm looking for a good, rust free, economical frame in size
XXcm. If you have one, send me a pic and your asking price." I've
done this before and got some great deals. I got a 1987 Trek 560 (531
steel) for $75 and I got a mid 70s Bottecchia Pro for $100. IMO the
Japanese frames listed above should be available for $50 or less.
They are good solid frames. Maybe not quite as nice as a 531 or
columbus steel frame but well worth bringing back to life for the
right amount of money and effort.