|Basically an uber USB bridge to connect two different, perhaps very different, USB devices. There are USB bridges that one can buy now that support connecting two mass-storage compliant USB devices to transfer files across. However, I have many USB devices that aren't mass-storage compliant, but can have files transfered under Linux, like my 5GB Dell Pocket DJ. Being able to transfer files over with a portable device from, say, my digital camera (which is mass-storage compliant) to my Dell DJ, would be handy.|
The really impressive potential use I see for this is for devices that really should have USB host, but don't, namely PDAs. It boggles my mind that there are new PDAs shipping that have USB host on thier processor/SoC and don't bring it out (Dell x30,x50,x51 come to mind)! Windows CE/Windows Mobile PDAs typically use USB serial gadget for thier client port. With that, you can have internet going through the USB cable, hook one end of the uber USB bridge to a NIC (wired or wireless) and have it bridge the connection over serial to the PDA on the other side. I'm guessing something simular can be done with Palm OS PDAs, and a Zaurus USB network to network bridge could still be handy on Z's without USB host. On WinCE PDAs file transfers go over the often slow serial link, and that could be done with SyncCE, however, for music playback from a large source (where copying the files over to the PDA isn't practical) the bridge could be running an ICE/Shout/whatever-cast server and stream it over the serial link to a player on the PDA.
I figure something running uCLinux on an Arm7-level processor with a USB host chip and small LCD that could fit inside an Altiods tin would do the job. Other than this player, I'm looking at some stuff Atmel has, namely an Arm7 and a AT43USB380 USB OTG chip with dual host, and one client port, as another posibility.