>>kbumsi+(OP)
It's a very cool thing and through the magic of virtiofs I'm (almost) at a point at which I have a script that I can point at a directory with a Linux file system and boot it in a microVM in under a second.
It required quite a bit of trial and error because the components aren't very well documented and don't seem to be made for each other. I meant to publish something about it but never got around to it.