i wouldn't quote myself 100%, but i think the back panel is just illuminated with an LED lightbulb, that can most likely be replaced with a blue LED of your choice.
some of mine went out, and i will need to try to replace them. although i didn't see them when i pulled the radio out, you'll probably need to remove some more panels under there to get to them. i haven't tried yet.
but i know for sure that the light that illuminates the shift console on ATX uses an LED bulb. most likely its the same setup behind the climate control knobs
but the radio display screen is red. unless you got a blue one to swap with.
EDIT: well, i did some researching, and found this:
(i'm not sure about the rule of linking to other forums, but i see people do it all the time. so, whatever)