It's probably one of the old bicycle type saws. They do go for some big bucks.
As to your search, here would be my list of saws worth looking at:
Dewalt 788, the Delta version of the same, any of the green Excalibur saws both from Canada and Taiwan, certain Hawks, Hegners. Stay away from any saw that uses pinned blades or short blades. Common blade length is 5 in. , Pegas, although they will be few and far between because they are so new, and the newest Wen saw (not the $100 one) might be ok, Seyco which is very close to an Excalibur but a very good saw. They will be scarce though. PSWoods makes a good saw too but I've never seen on for sale used. One more suggestion, if you are into research, go to Scrollsaws.com. There is a ton of great info there on many saws.