H2O that was a good link, it's lookin like most of the LED lighting issues have been handled by the aftermarket now. I was just at radio shack and I picked up a couple of LED holders for for the liscense plate lights on my bike. I think they will work good for your underdash lighting. The UV leds won't light up much unless your wearing white socks. The white will, just try and get the widest angle for illumination. Peep this link
www.lsdiodes.com
I really like Samcats idea with the multicolored leds and the rheostat, that would be very trick. For me just having every led dim with the dimmer switch will make me happy.
This LED thing has become an addiction for me. Are there any 12 step programs for this?
Nick