Quickly off-topic, just joined, but have been using the site for years now. Invaluable. Glad to part of the site officially now.
Anyways, with an informal introduction out of the way, I think this one can join the ranks of 'rare' CDs.
http://vgmdb.net/album/6409
Been looking for the Fire Emblem Sacred Stones Character CD for months, I kick myself for not finding the one that sold on eBay for like $40 dollars or so last November. I contacted a member who owns one seeing if he was willing to sell it, but no dice. Seriously, I can't find it anywhere else on the web. I can imagine if one pops up it would probably have a 300 dollar price tag minimum.