Except for being "self hosted" and the "front end to git" we're building that as a commercial service.
Not much to show yet but you can follow us on Twitter for updates in a couple of months: https://twitter.com/plumacloud
We're also considering providing our CMS as headless via an API so that you can connect it to your SSG and make your own template, host it wherever you want, etc, but we haven't decided yet on the pricing for that but it would be much cheaper than our main product.