I'd settle for a glowstick mod...
One of the big annoyances with the glowstick mods in FO3, there really wasn't any throwable item other then grenades - and NPCs would react as if you had tossed a grenade when you tossed a glowstick. In New Vegas, we have a lot more throwables that aren't grenades, so it should be possible to hook onto one of those and keep the NPCs from yelling "Grenade!".
They don't need to be that bright either, only lighting up a small patch (a meter across would be fine). There are other ways to get lights, I just want something I can use to mark doorways and corridors. Something available in at least half a dozen colors that only weighs about 0.2 per item (maybe even 0.1). As long as I can see them down a long corridor, that's plenty bright.
Nor do they need to be super-sized where they stick out of the player's hand. I'm not interested in a light source, I want markers.

The collision mesh would hopefully be larger then the actual item to keep it from sinking into the ground.