Come to think of it, it's amazing that Apple haven't done a high-quality, nicely-presented (i.e. not looking like a plastic paper weight), remote-controllable dock, by which I mean just a dock with RCA-outs for connecting to any hi-fi with a spare pair of RCA-ins.
I know Apple are big on WiFi etc, but even so, I reckon a nice semi-audiophile remote-controllable dock (I must emphasise remote-controllable) would have sold in worthwhile numbers for them.
When you look at how many 3rd-party vendors have jumped on the bandwagon with all-in-one boom-box docks for the iPod, there must be a not-inconsiderable number of iPod customers around the world who already own a home hi-fi (of whatever quality level) and would love to be able to plug their iPod into it and remotely-control the iPod from the far side of the room, even if only with basic RW <- Play/Pause -> FFW - functionality.
....you raised a good point about the HM-901 dock, by the way; nice though it is, I don't think it is remote-controllable, which is a massive missed opportunity (yes, I do realise it would require more R & D to accomplish but they already know all the relevant code hooks for the firmware).
Damn.... the more I think about this, the more I realise that Sony are perfectly placed to churn out a remote-controllable dock for their high-end DAPs... They have the expertise and experience to engineer something like that in their sleep!