MuppetScalextric You clearly never tried Qubes. Its really well thought out. The integration between VMs is the best I've seen in the compartmentalized desktop space.
And yes, I have rolled my own. Various combinations of packer, ansible, and bash scripts with vagrant for some projects over the years untill switching to qubes. Qubes is more streamlined and still has a smaller attack surface than any of my hacked together setups. It gets audited constantly, esp Xen. The mailing list regularly shows issues they've found, along with exploit, mitigation and fix. Security audits is what Invisible Things Lab, the company behind qubes, does.