As long as you don't mind a little soldering, I suggest the LED Lighting Regulator, they provide the drive for the LED strips. You can buy a 5 meter reel of the LED's for a few bucks. When I'm doing stuff here, I wire with #28 stranded wire to the LED strips. The full kit is designed for people that don't want to solder, but there are compromises, not to mention they cost more per car.
As far as headroom, the strips and protruding LED's are only 1/8" thick, so you clearly get more clearance. If you're careful with the wiring, it's practically invisible. For domes I sometimes use #30 wire-wrap wire in either black, yellow, or white, whatever matches the best and is the least visible.
