Hi,
I’ve just released the version 0.7b of FireflyClient which includes a last.fm scrobbling support :
https://sourceforge.net/project/showfiles.php?group_id=212642
More information available on a thread on this forum about firefly client : http://forums.fireflymediaserver.org/viewtopic.php?t=7198&start=90
I know this is a client-side only solution (compared to a firefly media server plugin) but it may do the trick !
— caribou