I'd be quite happy to see how a fat MacOS machine is being used as a build-server for multiple generations of MacOS versions, as well as how it could be used (via Linux VM's) to also build for Android, Linux, Windows, etc.

Essentially, this subject is all about the build server destination; there is an award for how many different targets you can get from the same code-base, and being able to load up a fat Mac that approaches the nexus, is certainly of interest to us developers.

VM's are key tools in modern build environments. Having a fat Mac running multiple VM's to solve the target/build infrastructure problem is fascinating on all fronts..