I have thought about this very same thing for my full length roll bar. My only concern is that sanctioning bodies (SCCA, NHRA) would invalidate the rollbar if it was cut in to. Anybody have any insight into this aspect? I was considering a simple bolt on that would require only 3 small holes to be drilled - 2 for mounting screws, one for the wire.
I also thought about adding small turn signal LED's on each corner of the roll bar, but not too sure about that one.