I did this little mod on my XL Ranger some time ago, because I don't like the yellow color of the common bulbs on the interior lighting.
I cut a circuit board in the size of the lamp, and fit in 4 white LEDs on it. I really liked the look of it at night. See the pictures by yourself (I will own you a night picture):
(Click for enlarge)
PS: The older owner of the truck put a bigger lamp on it, and it burned the acrylic. I will try to make another acrylic lens totally cristal to put on there.