tbraquet: Cool mod. I want to do it, too, and had some questions:
1. Your 3rd and 4th pic are good. Great detail that shows what color wire you're working with. However, I have an '06. Are the wire colors, gray w/ purple stripe, the same for my truck?
2. Your 5th pic shows the splice you made. How did you splice it? Did you solder or use a Scotchlock? I think you soldered it, but I'm leaning toward the Scotchlock. Any tips/warnings for/against the Scotchlock?
3. It looks like you tapped into the dome light wire (gray w/ purple stripe) with a black and white wire. However, I don't see that black and white wire in your subsequent pictures. Where did you put it?!?
My LED lights should come in next week, so I'm trying to get as much info/planning done before hand as possible.