Just so you know, putting a large magnet to a hard drive does not necessarily destroy it. It's more likely to just corrupt the data, requiring a reformat. I've done these tests with floppies and zip disks, the only way I can think of that a HDD may be different is if the magnet could damage the read/write head...
On to what you're trying to do...I seriously advise against this. Be happy with the iPod you have. Products do not last forever...they always get replaced. As competitors add new appeals to their products, of course Apple isn't just going to leave the iPod where it is to get run over. You can't expect there not to be a regular update cycle. It's just something you have to live with...if you keep delaying a product purchase to wait for the next version, for example, you'll never be satisfied. Why not be happy with your iPod as it is? All that aside, you could get into serious legal trouble if you are found out.