If you wanted to do it on really old Apple devices, I had Linux running on an iPod photo back in 2005 or so. It ran Doom, and also worked as a Redbox (there were still a few payphones around back then).
But yes, it'd be nice for something not quite that old too.
The hardware is well built but the apple lockdown says I can't get alternate OSs on this thing. You can even go back to the original ios version - because of jailbreaking.