hard to say what they're worth. ricercars started at ~$24, and were only available for a short time some years ago. I got mine more recently on eBay (same price) but that's the first time they've shown up in the last several years.
ricercar spos: really odd duck. It's probably the best construction quality I've ever seen, but a lot of the design aspects are hastily thrown together. It's one of the hardest cherry keyboards to take apart and reassemble. I have seen them sell for $100 in the past, though I'd not pay that much (too expensive for 2kro)
I used one for a while: overall excellent keyboard, one of the best cherry has ever made (that I have seen. A lot of their older stuff, eg g80-2100 I have not seen, but may also be of good quality.)
It has POM keycaps that appear to be laser etched rather than engraved/infilled. These have the same feel as blank POM, and are thus some of the best keycaps I own. I'd say it's worth the price just for that. I don't know what they did differently (or why) but these caps are very hard to come by. well-worn infilled ones feel similar, but the legends wear out fast. These are much more hard-wearing and still feel great. no "bump" like you get on normal cherry infilled POM.
edit:
http://austin.craigslist.org/ele/4579097986.htmlImage is not a ricercar spos (looks like a g81-8000) check with the seller about this. If it's NIB as he says then it is somewhat rare (there were like 250 or less produced, and almost all were available used. I have only seen one other NIB example for sale and I should have bought it.)