My big wish list item for this would be a clickwheel. But I'm guessing the ones Sony is using are made in-house. But super cool!
https://electronics.sony.com/audio/walkman-digital-recorders...
The Tangara music player has one as well. And the hardware is open!
You could make your own clickwheel pretty easily. 3d printed detents, abec bearing, magnet and a hall effect rotation sensor.