get an ohm meter and measure the resistance of the light on and off, and then buy yourself some LED's, wire them up and place that amount of resistors on them, and you should be set!
Check out http://www.julianos.com and look under lighting in their online catalog - the new catalog they have sucks, liked the old one much better, but they've got some nice ones.
I have a vert too and want to mount mine off the decklid of the trunk towards the top, let me know what you decide on and include pictures.
Hmmmm...i've got a 3rd brake light on my notch...but then again, it was a police cruiser too..not sure if you could even buy one though but here's a pic.