I played around with "evtest" yesterday and it looks like I can keep the SDL input handler and just add another "thread" to read the input events from /dev/input/eventX.That would first require the SDL lib on firmware to be modified to generate events for it. Or using Xlib for that.
Only annoying thing is that the kernel sends a lot of key events if the hold switch is triggered, so I'm not sure if it will hurt power consumption.
I don't think rockbox does this on any target. You could ask on the rockbox IRC channel or on the rockbox forums though.Would it be possible to add the ability to hear the audio when scanning?