You know, the classic Johnny Castaway screensaver. But as a Service™. Give it a RTMP_TARGET and it will push a RTMP stream including audio.
Sadly, I cannot distribute the actual screensaver or Windows installation with it, don't wanna get sued for copyright stuff. But I'm sure you will be able to find those files on the mighty interwebs, and treat the johncast folder as a C: drive. Put the windows install there, build a image, and have fun!