Sorry for my really late reply...right after I started this thread, I got quite sick. But anyways, that's besides the point. :P
So to answer your first point, I actually don't have an iTunes library anywhere. At least, not in the sense that my music is in the folder that iTunes can use to create its library. The reason for this is that I use the stand-alone application Floola (copied to a folder labeled "floola" in my root iPod directory) to copy music to the iPod. I suppose there might be some kind of database that Floola creates in order to keep a listing of what music and files are on the iPod, but I don't know for sure.
I see what you mean about the iPod's hash check and how that can cause issues for third-party album art applications. That's unfortunate...
I can add album art manually with Floola as well, and it works ok for the most part. But once or twice my computer crashed while the iPod was connected via its usb cable, and I think Floola was open as well. That caused my album art to disappear, and I haven't really felt like adding album art manually to 400+ albums. :P Floola also offers the option to "Save artwork in files", as well as an option to "Rebuild artwork db". From what I can tell, this system would be used after I manually added the artwork to each album, and then saved the artwork in the files, whereupon I could rebuild the artwork database in the instance that something happens and I lose my artwork. How would this work in the case of the hash-checks?
Again, any help at all is appreciated.