Hi yerp.
I don't believe it is possible for an "oggfs" to work in the same way as mp3fs because OGG is a variable bitrate format. In mp3fs we use CBR (constant bitrate mp3) which means we can accurately predict the final filesize as soon as the flac metadata has been read (i.e. before any transcoding), this allows filesystem operations to be very fast (e.g. 'ls -l' which uses 'stat'). With ogg...