All initial reports claimed the Epic 4g (and all Galaxy S phones) could use this cable to output HDMI. I can't find any recent information to back this up.
Are you sure this is not compatible? I did not post this in the wrong section. Do we really have no video out option on the Epic?
edit: Look at the eBay listing. It specifically says it's for the Galaxy S ... And lists the Epic 4g specifically!
edit2:
http://forum.xda-developers.com/showthread.php?t=737825 <- XDA thread. Verdict: Doesn't work now, but might be possible with a software update (Nov14 update anyone?)