Henry, I bought into Contax about six months before they announced its demise. My plan was to shoot film until I could afford a digital back. Since then I've accumulated most of the system's lenses and a slew of accessories, plus a spare body. I have not regretted the decision one bit; the system is ergonomic, rugged, and reliable, and I've been blown away by the images this system will make for the photographer with some regard for craft. Battery life hasn't been a factor for me: I use the MP-1 anyway with NiMH rechargeables, and recently started using the Li+ rechargeable 2CR5's internally. (They are especially handy in being little affected by the cold.) I've not yet found the "slow" flash sync speed limiting, but I can see the point.
I track prices closely on that auction site; certain accessories command irrationally high prices (waist level finders for >$600 are not uncommon.) The 35mm and 120mm lenses are scarcer and more expensive, while it seems you can barely give away the 80mm (the "kit" lens for this system) and 210 (it has an undeserved reputation as a real dog.) If you can find a 350mm it'll cost you; they've appreciated about 10 or 15% in the 5 months since I bought mine. Ballpark, lone backs go for $800-1000 or so; kits for $1500-1700 range. Otherwise, price fluctuations seem to be cyclical; haven't figured out the rhyme or reason for this. There was a peak just before photokina, apparently due to rumors swirling of a Contax renaissance that failed to materialize.
The system's termination threw the digiback picture into confusion--for how long would digital back makers continue to support a "dead" system? I know Phase has thru the P45; others can speak to its availability in contax mount. (What about the other makers, folks?) It's certainly rational, as a number of photographers have done--not just Michael R--to balk at plunking down P45-level dough on a "dead" system's mount, and to switch to the Hassy. You do hear those guys mourning their Contaxes, though, and Hassy has p***ed a lot of them off with its latest moves.
I began shopping for a used Kodak ProBack in the spring. At the time it was the only one available in my price range. Prices in the Contax mount have been significantly higher than in hassy or mamiya mount, and the backs have been very hard to come by--I've seen none at all there for the last five months or so.
I've been quite satisfied with the image quality of the back, if not with some of its operational quirks. (Try shooting skateboarding photos with this rig! ) Lately I've seen Aptus 17 refurb backs going for around $7500. In retrospect this would have been a smarter purchase than the kodak back. What can you do except do the best you can when it's time to act?
Sorry to ramble on so. To summarize: it's a great system; it's still available, though prices will fluctuate. Should be able to find a few refurb or new digital backs for the camera. I figure that I'll use mine for the next 3 to 5 years or so or until something irreplaceable breaks. (I'm not a full-time pro, and can afford this lower level of certainty.) By then there'll be a Hy6 or something better with my name on it.
Best of luck,