I looked up the one 'Madaboutmx5s' has pictured in his post and it does have the USB port here is a link where one is for sale on ebay:
http://i.ebayimg.com/00/s/NzMwWDE2MDA=/z/b30AAOSwpDdVAmhq/$_58.JPG
I also looked up the Retrosound model Two that Cxmoney has in his post and it has a bunch of inputs including a USB if I remember right, there is also a Youtube video about it.