Well, the Duos have been 'retired' for over a decade, so finding anything directly for the Duo is going to be difficult. If you want something portable, you will need some kind of Minidock. At least a 'standard' Minidock plus some other device (like the SCSI-to-Ethernet device,) but an Etherdock really is your best bet. They pop up on eBay from time to time.