I'm late to the party as you posted this way back in summer, but just in case you are still interested. For all my Spock/McCoy needs I rather love the spockmccoyhaven over at yahoo!groups: http://groups.yahoo.com/group/spockmccoyhaven/
You need a yahoo account to access it but it's still a very active community and has been there since forever (well, over ten years by now).

Also, check out the corresponding archive:http://spockmccoyote.tripod.com/
I don't think it gets updated anymore but there are many stories archived there.