how hard would it be to use/create an interface like this to stream music?

Hmmm. Not too difficult. I was planning on creating a third window, similar to the "now playing" window in Charcoalgray99's XML interface. It could theoretically be used to download and stream the current FID to WinAmp.

However, using the controls on the EmpegFace application to control the stream wouldn't work. You'd have to use the controls in WinAmp to control the stream instead.