As understand it the iPod will provide a digital output to go to a higher quality external DAC. It is available from the docking connector, but only if the receiver uses a proprietary protocol that is only available to third part manufactures on payment of a licence fee.
I cannot see that this is in Apple's short or long term interest. It must be in their interest to see the iPod used in as many situations as possible. Surely it would be better unlocked, and yet better still if the jack-out also provided S/PDIF as in their laptops and Minis?