Hurlbat Limited has a Kickstarter campaign running for a 28mm modular Gladiator Arena terrain kit. They’ve made their funding goal several times over (granted, they weren’t looking for a lot to begin with, but still), so it’s stretch goals from here on out.
From the campaign:
Welcome to the first Hurlbat Limited Kickstarter campaign. We have built a prototype modular 28mm scale gladiator arena and we want to raise funds to develop it into a polished retail product.
The arena is available either as a kit or completely assembled and painted. All of the curved sections use the same footprint so can be swapped around to give a variety of layouts and new straight sections will allow for different arena shapes. We have designed arena floors which suit a variety of games and these can be bought separately from the arena sections.