I've thought about this, but never did anything. I was wanting to get an extra light just like the one over the front seats and put that back there with whatever trimming was necessary. The rear light could probably easily be run directly from the front light without having to run something all the way to the fuse box. I never did it cause i'm kinda lazy with the focus, and if i'm working on cars, its on my mr2.
I had a 3' neon light wired up to my dome light switch in my old Mazda. It fit pretty nice, and with an adapter plate over the old dome light hole, looked pretty damn good too.
____________________ Project FocusFast
'06 ZX3- Intake, exhaust, mount
'01 ZX3- Salvaged, SOLD
'01 ZX3- Repo'd several years ago
'80 RX7 SA- Where the f*** did THAT come from?