I mentioned this dilemma while teaching a class at this year's Fox Chapel Open House. One of the participants mentioned that his wife uses something called a quilting pencil to make marks on dark fabric.
I went to a local shop that teaches quilting and sells supplies, and sure enough they had one. It wasn't inexpensive, but came with extra pieces of lead, so I decided to give it a try. The lead is still quite fragile, and I broke a few tips until I figured out how much to let out, but it does give a line that is thin enough to use as a cut line, and shows up nicely against the dark wood.
So, if you've faced a similar problem, here's one solution. If anyone has others, please let me know and I'll get the word out.