I just got these in today and they seem to work pretty good. The length is perfect for my phone (iphone 6) and the volume and player controls are retained. Also the fact that it's an L-jack is nice too.

http://www.amazon.com/Seadream-4-Pole-Female-Headset-Extension/dp/B018UHLFYO/ref=sr_1_4?ie=UTF8&qid=1462228916&sr=8-4&keywords=3.5mm+4+Pole+Male+to+Female+Headset+Extension+Cable