I may have just found my Astell & Kern AK240 replacement.

"Portable DAC & Headphone Amplifier. Designed for serious headphone users. Up to 1TB music storage available.*"

The website does not indicate if you can control tunes through the unit itself or via another interface.

Looks great. Maybe you can use the line out in to your car to get some great tunes?

No complaints with the AK240 but I believe Aurender is forward thinking by allowing flexible storage integration. Bravo!