I guess I got to using facebook a bit. Sorry LJ land!
Original Nerf Firefly
The modification.
Edit: more info!
The green barrel was painted with leaf green sun-catcher paint (have to be cautious about the tacky, long dry time of that paint. can't expect it to be perfectly clear).
The 8 'dart holders' in back have a string of battery powered white led lights (now also green with the suncatcher paint) beneath them, illuminating green glowsticks. The batteries/switch for them is concealed aside from the guns original battery compartment.
The light on top is one of the newer (and great!) cheap 8 led flashlights, taped to the add-on scope track (scope removed - was useless, inaccurate) that came with the 'CS-6' gun. The green filter on its front came from a military flashlight (was incandescent... so outdated XD)
My one change I am still looking to possibly make-
to make it more 'sciency' would be to place slimy green lizard fishing lures in test tubes, suspended in the glow stick fluid in the place of the glow sticks. However, finding 8 plastic test tubes of the correct size (long, nerf dart diameter) for a reasonable price has proved problematic.
And of course, I took out the air restrictors and improved the seal, increasing the gun's power. :D