I was trying to do something similar last year and gave up because it felt futile. That said, it was the push I needed to try Rockbox, and I haven't looked back. Managing things via the file system is really nice.
I started on my Linux box and despite many apps claiming to support iPods, none would actually work. I ended up getting an old Mac mini running again and I’m using that for now. I’ve never given Rockbox a good look, I should check it out.
