There is this plugin for SMF: Joomla-SMF Forum Component SEO Plugin for ARTIO. Can it be used or converted for FireBoard?
Negative...
First, this extension (or hack, really) is for use with a bridged SMF forum (a forum that operates completly outside of Joomla). Fireboard, however, it way too cool for that

It uses and relies on Joomla to operate, so no bridging is necessary and neither are any ugly core hacks.
Secondly, because it's listed as a commercial extension, it can not be modified and released to the public (under any license). The only one who can do the modifying is the author, but it's unlikely that would happen -- as I mentioned, Fireboard works much differently than SMF.
So, in the spirit of keeping things simple, all that is needed is an sef_ext.php that all three main SEF components can use.
Anyone experienced in creating sef_ext.php plugins and willing to contribute to this awesome project?
Sean