Fog Creek likes plugin developers. They're awesome! Anything we can do to help facilitate growth in that community is generally well worth it for us.
If that means a dedicated FogBugz site for you to share (even if just the wiki), or a dedicated SE site... absolutely! Comment appropriately if you want that, and I'll get it done. This hasn't happened yet because we weren't sure it was wise-- FogBugz.SE seems most important. If you just need a front end, you can always use one of our free 2-user On Demand accounts.
There are also things like http://fogbugzplugins.uservoice.com/, which provide some types of feedback and community interaction which StackExchange isn't yet capable of. As SE evolves, it may completely eclipse uservoice for our purposes, but that is yet to happen. The plugin requests poll is an experiment to see if SE can beat out uservoice for our needs... The jury is still out. It's a little awkward that both exist simultaneously.
We haven't taken a lot of initiative on this, since we suspected that a superior way might emerge organically from the community, however we're open to nudging people toward a set of best practices via website text, etc.
So, the question is:
What do you think Fog Creek should do to best strengthen the FogBugz Plugin community?