so, a goofy idea POP'd into my head today; if you had clear resin and some Old Marx tank cars and a few safari Toob figures you could make a riff on Mommy Fortunas Circus from "The Last Unicorn" in O gauge...  I'd just replace the tin cylinders of the tank cars with clear plastic ones and colored resin "water".  maybe a few aquarium oddnobs like tiny sea stars, sand and glitter...  and of course you need to find some figures for Mommy fortuna