So in researching the Tip / Ring / Sleeve connections, I see that a mono (Tip / Sleeve) would do the same thing as what I was asking for, so I just need to find a nice mono cable and I will get the left / right shorted together?     basically what was already said:  

  So for source it is always either my Android or iPod classic --> headphones (unfortunately nothing super HiFi high end, some SMS Audio "Streets" at the present).   I am not aware of any way to do mix mono at either of these sources, but I am happy to learn of new options! :-) What I am...

yeah my OCD hurts when I have more plugs than I need 

Would anyone be willing to make me a 3.5mm stereo plug to 3.5mm stereo plug, braide cable, but wired mono? (left & right soldered together)   I am deaf in one ear and would like to use newer headphones, but get both channels - I know it's not stereo, but it's better than 1/2 of the sound...