I have a feeling there isn't gonna be much in there, haha.
Now back to the power generation...here's what I'm thinking.
cut off the legs from the stock coil and put 3 more coils in there as my drawing shows. The mounting bracket would probably have to mount at the holes for the cover, and something would have to be figured out for the cover...maybe use studs and thin nuts to hold the coils, then notch the bottom of the cover so it can slide on the studs and not be effected by the nuts, then nut the cover in place.
Anyway, then machine a new rotor out of steel. I think it's 1 3/8" diameter or so, not sure of the thickness. On each "pole" of the rotor, machine out a circular space for a magnet (N50/52 would be best, N42 would still be better than stock). magnet should be just a little smaller than the thickness of the rotor. These should be epoxied in place, one with N out, one with S out. Obviously you'd need the center hole in there, with keyway if that's how the stock one is. (make sure it's keyed the same as the stock so N is in the same spot relative to the keyway)
The 3 other coils should be wound to produce approx 5v each if possible, with 20-22ga wire. This is to account for the 1.4v drop you'll get if you try to bridge rectify to DC, and will provide the proper voltage for charging a battery if the user should choose. 20ga wire will provide for 132w, and 22ga would provide 84w. These would be connected in series, and have a completely separate ground from the stock ignition coil. (yes this would mean a whole two wires going to the lights.)
...I think that's all I got.