So, you're looking for something like
this?
I have no idea why lashing two identical cables together didn't let any signal through. I'm sure one of the techies around here will be able to answer that question. Ironically, I am also looking for something similar...only I want the right-angle plug on only one side.
Hard to find to say the least. I may have it custom made, but it may cost more than the convenience is worth.