Not a clone, I've been developing a blogging platform with the same basic feature sets called CiiMS [1] since 2011, which is written in PHP. Unlike Ghost however, CiiMS has a working API, comprehensive documentation [2], and a dashboard. We also offer our own hosting as well [3].

[1] https://github.com/charlesportwoodii/ciims [2] https://docs.ciims.io [3] https://www.ciims.io

There will be one somewhere (even though there are already a great many PHP projects covering similar use cases) though PHP isn't exactly a show-off platform these days so you'll not see it advertised loudly as "GHOST IN PHP!". Same for "Ghuse in Ruby". Maybe we'll see "Ghost in Go" or "Ghost in Clojure" soon though.

Ghost in go already exists: https://kabukky.github.io/journey/

and is my preferred blog platform.

Wouldn't that pretty much be wordpress? (expect it's not a clone - it came first).

Wordpress with a cleaner architecture and a more modern API wouldn't be a bad thing.

Maybe give the WP REST API a spin.

Very active development, but needs more real world examples before its ready for WP core.

http://wp-api.org/

Well... no thanks. :)

Wordpress has some undeniable qualities for quicly building simple websites. Making it a whole framework for apps and big websites just sounds silly to me.

If I need to build large webapps I don't see any reason to do it with Wordpress (or even PHP) nowadays.