I have a barely used iPod/Aux adapter that fits the REC radio. It may fit others. It shows up in the Mode screen as VES, so if you have VES the audio won't work, but the video and wireless headphones will.
I got rid of my iPod shortly after I bought the adapter and since I don't use the Aux input, I don't see any need to have something extra plugged into my radio. It works flawlessly. It has an iPod cable interface and does charge it whether or not it's playing.
The Aux input is a red & white RCA cable. I have and will include a 3.5mm to RCA adapter, so you can plug it into the headset jack on most Smartphones, MP3 players, etc. . You can get a 3.5 to 2.5 mm adapter to use with other devices or you can get a 2.5mm to RCA instead.
I don't remember what brand it is, but it's nearly if not identical, to this one http://www.ebay.com/itm/RAK-REC-RAQ-...item1c1d9d054e
The connectors on it are all the same and it functions exactly as described in the link, but may be a different brand.
These are $100 new on eBay. I'm asking $60 shipped.
PM me if interested.