FYI: Here's my little minimialist starter kit called Hello, Minima! - Get Started w/ GitHub Pages (Jekyll) in 60 Seconds using the Minima (Gem-Packaged) Theme [1].
We run https://www.shoto.io completely on Jekyll. Until now, all modifications we needed were possible. I wonder if it is super future proof though. Once we start expanding the site with new features we might start "abusing" the setup.
In any case, I think the data is stored as MD and thus it can be probably easily migrated.
I will! I am going to add a note to the post letting people know. Maybe we can create a similar functionality that Jekyll Now had of forking the repo and having a github page right away.
[1]: https://github.com/henrythemes/hello-minima-theme