Makes sense! Thanks. I'll update here when I knowIt may well be not an option on the configurator because they know exactly how to fit all the components into the cases they have already, however a different case entirely may take a lot of research and testing to make sure it a) it fits and b) doesn't have heat issues.
Admittedly this is complete guesswork on my part as I've never looked at the sizes of the mini PC cases nor what they look like inside.
But yes definitely worth asking them about it, let us know what the response is (noting the emails are taking about a week to get a response I think)