Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

If you have a 3D printer, this fellow is selling some nice looking STL clock files to print that seem somewhat practical:

https://www.youtube.com/channel/UCWbKinQBavrH3iPMvgzVQzg/videos

His one pendulum clock has a 32 day run time.  I keep thinking about giving one a go, but I already have so many other projects in the queue.