Any OEM cd changer from a Bose equipped Nissan/Infiniti from 95-01 will work with your vehicle.
I have one up for auction right now if you are interested:
http://cgi.ebay.com/ebaymotors...&rd=1
There are also auctions on E-bay for the OEM style aftermarket brand called USA Spec, model # SCD-N66 and SCD-N66E. This brand would require you to rewire their harness to the trunk as it isn't compatible with the existing harness, even though it does plug directly into the headunit.
E-bay is your best source for a good deal on a working unit without getting ripped off by the dealer.