That's pretty much what I had in mind, except I was going to leave the old light fixture in place and jumper off the pullchain so that it will turn on both lights. I'm just not to certain if mounting the light to the board would be any sort of code infraction.Think outside the box (pun intended) :jester:
1) Remove the existing fixture.
2) Connect a short piece of wire (romex if local codes allow)
3) Place a blank cover plate over the existing ceiling box, with a center knockout removed. Run your short jumper wire through that knockout with an appropriate connector.
4) Cut a hole in the center of your board, using a "pop-in" box or even a "Pancake" box for your new fixture.
5) Run your jumper wire to this new box.
6) Install another wire from this new box as your switch loop, fish it down the wall and install a wall switch.
7) Make up your new ceiling box, and mount your new fixture :whistling2:
I even had in mind to crimp some push-in connectors on the jumper wires in case the board fell or someone comes after me and pulls the board down without realizing it has hot wires run to it. That way the connectors will pull apart and cut the power to the new fixture.