I read the post about the delay on the radio until you open the driver door and thought about this feature that I like; My grandparents Park Avenue does it. When you get into the car the lights all come on and stay on for a while, then they slowly dim after about 10 seconds or so. I really like this feature, it's softer on the eye than the full power shutdown, especially in my Electra, because there are quite a few lights in it. What would be required? A dimmer relay or something?
Check out http://www.webelectricproducts.com/products.htm, and click on "Dome Light Dimmer" on the left side. For $40, they have a pre-made system that will dim your lights. A little pricey, but you don't have to put too much thought into it designing a circuit.
