I think that Greenwich Electronics sells individual direct replacement relays (part # AR7-012-CQ6S). They have a direct replacement catalog that lists the original Fujitsu relay as the part mentioned here. The replacement is a quiet relay and should not loud click like the NEC many people substitute the Fujitsu with. I'm going to place an order through them and post how they perform/fit.
Here's the replacement guide:
http://www.geirelays.com/acrobat/crossref.pdf