AWESOME! I was just thinking of doing this the other night, I'm glad I found this thread. I'm in the process of outfitting my XC70 to be more useful on camping trips, and interior lighting like this is high on the list. I think I may also put some IN the car around the cargo area as well, to light things up inside as I plan on setting it up for sleeping.
I was thinking of powering the in-car ones by one of the USB rechargeable batter packs for charging phones and whatnot, anyone try that setup? I don't want to get into hardwiring anything into the car, I don't want to mess with the wiring. I feel very fortunate to have a 11 y/o Volvo with over 200k miles and no electrical problems! (knock on wood)