I'm an Electrical Engineer. If you're just looking to plug your iPod into your stock radio and you want to take the time to dig up the schematic for your specific radio, I can work up a BOM and instructions for building/installing a cable that will output audio and charge your iPod. There's some pretty fine soldering involved with Apple's 30 pin dock connector (you'll need tweezers and maybe a jewelers loupe depending on your vision) but with the proper tools and some patience, it's possible for a DIY'er. Would cost <$10.