There was discussion of making an ethernet dongle for the player. I can see how that would be a useful thing if you were trying to taxi files to a Mac and didn't want to bring the dock.

But I have to say, the dock is smaller and lighter than the player itself and easy to take with you if you know you're going to need to taxi files to a Mac or a PC without USB. The only time I'd see needing an ethernet dongle is when you're in a place where you need the ethernet connection unexpectedly. But in that case, you wouldn't have the dongle either.