https://en.wikipedia.org/wiki/Rio_Karma
After my Rio broken (failed HD, and a terrible pain in the butt to take apart, and beyond my skills to put back together...) I got an iAudio X5 L and stuck Rockbox on it. After a few years, I upgraded the HDD to a CF-Card using a CF-to-miniIDE adaptor. I loved the battery life on that thing.
https://en.wikipedia.org/wiki/IAUDIO#iAUDIO_X5
But, sadly, now I just use a phone for everything.
I am very happy though that I can at least have foobar2000 on my phone. But, I really miss the well thought-out tactile UI of my previous dedicated players.