I been looking at the clip it seems like it has all the tools necessary to be able to process noise cancellation. Perhaps we don't have the correct algorithm to cancel out the noise to sound ratio.
This seems like a possible since:
-1 it has a microphone
-2 rock box developer are simply amazing and talented
-3 i use my 12" headphone cord all the times and i clip it on my shirt collar.
-4 it seems like it could be use throughout majority of the rockbox port who has microphone port.
I understand battery usage will go up but it's cheaper and more convenient then buying a noise cancellation headphone with a battery. Plus I hate long headphone cords, I prefer lightweight and freeflowing as possible :]!
Thanks!