[tbe]

This reminds me of Bedrock Linux, which allows you to run multiple linux distros on a single kernel instance. It does so using good old chroot, but has an implementation that is capable of breaking out of the chroot when entering a new one. This way the different environments become more integrated in that a RHEL binary can call a Debian binary and so on, creating a sort of super distro which is itself quite small and simple.