Ah yes, good replies, one and all...
After reading (more of) that faq, and general browsing around the internet, it looks like I'll be after just a plain ol' Anglo in G/C's. The Rochelle looks to be in my price range, and some places offer a trade in when you're ready to upgrade, so why spend $700 on one with a key in D, when I can spend $350 on a G/C and learn the damn thing. So, yeah, a Rochelle G/C Anglo? Sound good for a first timer? The offerings on eBay aren't all that interesting yet.
We don't have to do everything in D, and if you ever heard a shanty band, you know that keys aren't really all that important anyways.
Our little troupe of singers varies greatly in members, so having me poorly play a concertina occasionally may be independent of the fact that there is someone playing the pennywhistle (or main pennywhistler has now got some sort of lung disease now whereby his doc said he should cut back on singing and whistling, yet apparently, Marlborros are still OK).
http://sendthebastardouttosea.com/
edit:
Well, this one is on eBay. No idea about the brand or key, so .... eh....
http://cgi.ebay.com/Anglo-Concertina-Accor...id=p3286.c0.m14