I got a dome light fader from Web Electric.
http://www.webelectricproducts.com/products.htm
It works great. Model DLD-1 Dome Light Dimmer Module. I installed it next to the fuse box and hooked into the dome light wiring right there. I also installed two under dash lights to light the footwells and hooked them in. Lights fade out in twenty seconds when the door is closed but go out instantly when the key is turned or the truck is running. I didn't have doorswitches so I installed them in the rubber bumper holes at the top of the doors... much easier to wire and no drilling.. Drilled out the bumper and it fit over the switch too.