Thought I'd see if there were any likeminded individuals around.
This is three of my small collection that I have with me at work. The 4G Classic (left) is modded with 64gb, the Mini is 128gb, and the 7G Classic is currently in need of storage and battery. My plan for that one is to give it 512gb and as big a battery as I can squeeze in there.
I've never really been a fan of the iPod, but I had an older one that you could load custom firmware on, which extends the life of the device. I never really used it, just messed around with it.
A good number of iPods can have Rockbox loaded on to them. I did it on my 4th gen, but ultimately preferred the original firmware.