If you own more than one iPhone or iPod, then you may want to check out the Parasync dock which can sync up to a total of 20 iPhone’s or iPods at once.
The Parasync dock is compatible with the iPhone, iPod Touch, iPod Classic and the iPod Nano, and it can charge and sync up to a total of 20 devices at once with iTunes.
I suspect this is aimed more at the business market than the consumer market, and it is compatible with Mac’s and PCs although the manufacturer does state that it may not work as well with a PC as it will with a Mac.
There is no word on pricing or availability, it seems you have to contact the manufacturer direct for a price.
Product Page via Gizmodo