Sorry to say – but I’ve dropped support for ffmp3 – the main reason for this is that flash only processes audio at 44100Hz so streaming ogg and listening with ffmp3 wasn’t possible at 48000Hz (it was just play-backed at 44100Hz). So I needed another solution for this. Its name jlGuiApplet which implements an Winamp-style Ogg/MP3-Player as a Java-Applet and supports the 48000Hz sampling-rate as well. This software is almost 5 years old but it does the job.
As you can see on the ssh-terminal running on the XportPro – streaming to 1 client produces around 1% CPU-Load at 128kbps. Also note that we are using more than 8,5 Megabytes of RAM, which means that older XPortPros with just 8Megabytes in RAM total, won’t be able to run the full OggStreamer-Software including the builtin sighttpd streaming-Server.
OggStreamer 
Did you give a look at http://jplayer.org/ ? In HTML5 mode it can play Ogg streams, but I don’t know if it has sampling rate limitations.
Thanks for Link – didn’t know about this project. – I’ll definitely try out jPlayer 🙂