We occasionally descend things that require more than rim or disk brake to survive, so there's a dedicated drum (only) on the back of our trekt2k. I also don't want to wear my rolfs out, ever. An I'm an occasional weight weenie, and curious about brake alternatives, so I created a lighter drum brake for light duty tandeming.
Bought an extra arai drum ($30), put it on a lathe and removed the heat sink fins. Then I performed mental finite element analysis and swiss-cheesed the over done brake shoe metal. Then ground a bit of excess material from the backing plate. Its lighter, still not sexy, works fine. If I tour or decend anything significant, I'll put on my other (stock) drum.
Might have removed 1/2-3/4 pound. So what. Guess I had too much time on my hands.