I'm not experienced haskeller, but I've started to work on augeas property for propellor. I've created a separate repo for it: https://github.com/paluh/propellor-augeas. I will try to rewrite some existing properties on top of this and add some new. It is in a really early stage, but it works.
I think that it will be a lot easier to work on propellor core properties and features, if it will be separated lib without any "spinning" abilities. Currently when I'm trying to read your or my commits history, there is a lot of "propellor spin" commits, without any sensible comment. In addition, it is hard to merge any changes to your repo - I can't just send you pull request. In case of such a broad project as propellor, I think that it will be beneficial to facilitate cooperation and to separate deployment mechanics from core configuration management parts. What do you think about extracting pure library from existing project?