This is a great little Five cylinder Stirling engine by Jozafax on Youtube. It looks like he has put a lot of care into the fabrication and assembly of this engine.
Skip to the first minute mark to see the engine running.
He also has a set of instructions available his website. The instructions are very clear and have a lot of pictures and helpful diagrams.
I would assume that linking like this to make a five cylinders Stirling engine would improve the torque of the engine. I would be fun to test.
I think it would be fun to link several of these together to see what kind of work could be done. Maybe 8 of these five cylinder Stirling engines to make a 40 cylinder powerhouse! Maybe you could even run a small power tool like a drill or maybe a Dremel tool.
I like this type of project because it shows how creative minds can make so many new engine configurations. Very inspirational!
I will definitely put a multi-cylinder Stirling engine on my build list.