I could have sworn the recent update brought USB capabilities up to 24/384, though I can't say I've checked that personally. Also, I thought they had claimed DSD128 support was coming in the near future but now I can't find it anywhere so maybe I dreamed that part. I can confirm that DSD128 does not work at this moment, at least with the files I have played through the SD Card reader.
But this is all easy stuff for them to update, and I'm sure it will all be set sooner than later.
That would require a display as well as a control panel, which I'm not sure would comfortably fit on a device that small. I can see the appeal but it just doesn't seem feasible to me.