When I am traveling I am currently limited to using the built-in mic for Skype calls, with my stereo earbuds that I use for listening to music for audio out. I'd like to use a small, travel size boom mic for Skype calls, something like the Plantronics MX500i. However, I am very confused on how the headset plug on the rMBP 13" works. It needs one of these 4-contact 3.5mm plugs. Does anyone know if there are adapters that will make that work with headsets like the MX500i? I would also not mind going for a USB headset, but ones I found (like the Blackwire 435) dont have Mac drivers. Any suggestions? Thanks!