You could always hack into the wiring and install a toggle switch in the dome light circuit. /forums/images/graemlins/thumb.gif
I've also seen Jeeps with a little metal clip in the door jamb. It could rotate around to hold the dome light switch pressed down all the time, for use with the doors off. Then when you put the doors back on, the clips get rotated out of the way. /forums/images/graemlins/cool.gif