well... totally ridiculous and insanely ambitious... this engineers dream table; https://www.youtube.com/watch?v=VQ_AwFSWIPU here's a little more explanation
Of course this is way above my head and just too hard to reproduce in 1:12. There are a few mechanisms though, that come close to the same circular expanding feature, but those don't stow the leaves that increase the size of the top.
And that's what actually makes it so attractive to me. And is so useful in miniature too. That way you can 'play' with it without having a bunch of loose table tops you need to put in. A feature that made me make this table But a circular one is definitely on my to-dream-do-list