I think the problem with that is light from an entity does not apply to lighting up another entity (with blocks at least). The game as it stands would need to have an overhaul as to how lighting works, it's the same reason we don't have flash lights.
Spotlights would be great though, especially if their light traveled farther than the standard light blocks. I've got a station with a massive interior that just can't be lighted from above because of the limit that light travels. Plus, making a dry dock with spotlights would make everything better. Imagine spotlights in conjunction with the rail system. Lighter Lighten is a great solution for now, but even with that I like to put some light blocks down in addition to that for maximum clarity.