For the past 6 years, the Apple Mac Mini has been one of the most popular hardware platforms for Virtualizing MacOS running on VMware vSphere enabling our customers to develop and build iOS and MacOS applications. With that said, VMware has historically only supported two Apple hardware platforms: Xserve (now EOL'd) and the Mac Pro (6,1) which is officially listed on VMware's Hardware Compatibility list and this has been officially supported by VMware since 2012 when we first introduced support for MacOS Virtualization with the vSphere 5.0 release.
As many of you know, I have been a huge advocate of this platform for a number of years now and I have been working with various Engineers over the years to ensure that we have the exact same user experience when working with ESXi on the Mac Mini as you do with the Mac Pro. I still recall in the early days where it took several "hacks" to get ESXi to successfully boot and install.
Today, ESXi installs on the Mac Mini just like any other x86 platform. It runs amazing well for our customers, especially for a consumer device, who have deployed them in their datacenters ranging from a couple hundred to several thousands for some of our larger Enterprise customers, one such example is MacStadium, the largest Apple Infrastructure-as-a-service provider which many of the Fortune 100/500 companies are leveraging to provide them with a platform to build and develop for the Apple eco-system.
UPDATE (08/27/20) - Apple 2018 Mac Mini 8,1 has been added to VMware HCL which supports both ESXi 6.7 Update 3 (Patch 03) & ESXi 7.0b