I2s extender:
http://www.twistedpearaudio.com/digital/teleporter.aspx
nice one.
just today i’ve got this link from a friend:
http://hifiduino.wordpress.com/2014/01/24/diyinhk-isolated-xmos-usb-interface/
i’m monitoring the i2s market a bit as I would like to utilise i2s inputs of my PWD (spdif/toslink/usb are already occupied) and eventually improve the SQ over the bridge (that would be a challenge hehe 
)
Some more on the subject:
http://jlsounds.com/i2soverusb.html
http://www.amanero.com/