I did a brief search and found two docks with digital output: the Wadia (pricey at $380) and a DLO (somewhat less pricey at $200). For the price of the Wadia dock, you could get an AppleTV with a 160GB hard drive and transfer all the files to it, which could then be hooked to the 990 via optical and a video cable of your choice. You could also get a SqueezeBox, but you'd have to deal with accessing your audio with some extra software and you'd have to have the computer turned on to serve up the files.