Ok, so I was thinking (then doing, then failing), running lights mount to hardpoints. Guns mount to hard points. Guns mount to running light hardpoints. Therefore, lights must be mountable to gun hardpoints. Check.
Guns can come ready on a ship, as can lights. You can also buy guns. You can't buy lights. Let's buy me some lights! No check.

Lights are defined differently than guns (no !@#$, Sherlock!), much differently. But they're in a file called light_equip.ini. So I tried to see if you could buy and mount them on your ship. No dice. I figure the problem is with the fact that lights are very simple in their definition, whereas other equipment can go on forever with their parameters.

Has anyone thought up a way to fix this? Buying custom running lights for your ship would give it that personal touch. The DA guys were at one point quoted as saying that they want the ships to be player avatars, but with each kind of ship exactly the same, then they don't really work as such. Personalised running lights is just a little tweak to this, but would be a cool addition to the game. I'm gong to keep plugging away at this, but it's probably hopeless.

If anyone has any ideas on how to make running lights buyable, I'd *LOVE* to hear them though.