You may be able to find something at a computer parts store. The thing I have in mind is a media reader type thing. It would require some modification.
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3896256&CatId=942
That is too big and you only need usb and audio; don't know if they make anything like that. I know on some computer cases, there is a front port with USB and audio ports, you may be able to find something like that.
Might be pretty tough to find.
I guess you could just find an old computer case and rip the front ports off with usb and audio.