Wait a minute. The changelog for mt-daapd from 14 April 2005 says that the ivorbis-tools package is a patched version of vorbis-tools and that firefly may revert back to the official vorbis-tools release.
vorbis-tools is available as a mipsel package from the nslu2 feed.
Does anyone (Ron?) know whether the ivorbis-tools package can be reverted to the official release (yet)? That would make life considerably easier…