Fishing the Romex down the existing wall and into the panel--without cutting open the wall--was the tricky part. Since you've only got a half-inch diameter hole on either end with total darkness in between, it's a bitch and a half to do. The idea I came up with last night worked like a charm--the ends of the two Romex cables were taped together, and one of them had two wires exposed, stripped, and twisted back to form loops. On one loop I hung a Mag-Lite Solitaire flashlight, the other loop was to catch with a hook pushed up from the breaker panel. My original idea was to use a Photon LED light, but the Solitaire is narrower (the width of a fat pencil, instead of the width of a quarter) and fit into the attic hole much easier. (The attic hole already had two cables through it, there wasn't much room left.)
So now I have a working fluorescent light attached to the wall in the attic. It should light things up much better than the hanging shop light I've been using for the past three years. The switch for the light is just inside the trap door, along with a duplex outlet for powering tools. That same circuit runs up to the master bedroom closet, feeding another outlet meant to power all the chargers I'm relocating to a shelf there--cellphone, Pilot, handheld radios, and camera, as well as the new attic exhaust fan I want to install. (That attic gets *hot* once the sun comes out--five minutes after I go up there, I'm dripping sweat onto my glasses.)
The other Romex cable will feed the new power outlets in the back of the computer room closet. Right now, the computer rack is fed from a few too many power strips plugged into a single wall outlet. That outlet is on the same circuit as half the master bedroom, the garage, and part of the kitchen and living room. This just strikes me as... bad. So I'll have two new circuits feeding several duplex outlets in Wiremold down the back of the closet. Much neater and much safer.