I am one of the early contributors to WordPress (you'll see my name on wp.org's About page near the bottom), and one of the founders of the Habari Project. We started the Habari Project for many explicit reasons, but in part because the curators of the project (Automattic) were not behaving in a way that we felt was beneficial to the community they had begat. So let me tell you a little about our project:
Not only is the Habari Project an entirely Open Source platform, but it recognizes participants in the project appropriately based on their contributions, something that I did not observe during my tenure working on WordPress.
Habari employs the Apache Software License, which is more permissive than WordPress' GPL. Want to develop a plugin or theme? Is the code tainted by the GPL? In WordPress, I don't really know for sure what parts can be redistributed, if any. In Habari, you can sell your themes and plugins for profit if you want to, or contribute them back to the community -- most themes and plugins so far have been.
The passion of the Habari community for producing good, documented code has (in my mind) been one of the driving forces behind WordPress' "recent" adoption of similar policies. The quality and friendly tone of assistance I get from people who know about Habari has been consistently orders of magnitude better than anything I've seen come out of WordPress, which is a characteristic that everyone working on Habari strives to maintain in the project. One of our guiding principles has been to be a project that is useful for web development education; We've seen a lot of people join our project and learn how to code well, both in the method they use and in the collaborative environment our development often lives in.
We've accepted a policy of keeping up with as current a deployment of technology and standards as our core users can stand. We recently adopted a PHP 5.3 minimum version, and I'm pushing hard to take that to 5.4. Habari simply does not run on PHP 4, and never will because it's no longer secure. We code for HTML(5). We're using CSS3. Our roadmap (admittedly difficult to find online) includes PSR-0 and namespace adoption to more easily integrate with vendor libraries. The use of current technology and techniques is really good for developers, and a refreshing change from projects that insist on supporting every old (insecure) server architecture out there.
And I'm currently making a living (yes, paying the mortgage) deploying Habari as a CMS for clients. It is viable. It is open source.
I know first hand how long it takes to build a working product with a small community. We are admittedly behind in our implementations of some features that WordPress was able to steam ahead with due to their larger community. There are also non-dev areas like marketing where we could use some work. We've been trying (albeit weakly) to lure those kind of contributors to the project.
We had a talented designer help us with our current admin design, and one of the things people comment on most about it is how it's not as cluttered with st as WP's. I like the design you've used in Ghost because it's similar to ours, yet modernizes, and I think our community would like it, too. We've been talking heatedly about a new admin design for our next release...
Habari may not be the thing for you, but I do encourage you to take a look, visit our IRC channel on freenode, and take from it what you can. If you still want to try to bend a WordPress fork, I'm at least interested in the story of your effort and struggle. And if you want to chat about why we started over (though I think it's obvious, maybe it's not to everyone else) instead of forking, or why a new project with a handful of addons (compared to a competitor) can still be a contender, I'm happy to chat. Here we are: http://habariproject.org/