Just modified my 4G 40gb iPOD. Dropped in a new 1200ma battery (from the old 600ma), and expanded the hard drive from 40gb to 60gb. Just as I proudly showed it off to my wife, her jaw drops- only because she surprised me with a new iPOD.
So, now I would like to sell my labor of love. Parts have cost me $220, so that would be the minimum.