We are getting quite close to releasing themes for Posthaven. We have all sites running on our new theming engine and now need to finish up the new themes we are working on to make theming useful for everyone.
If you are among our more technical users (i.e. you know your way around the command line and know HTML and CSS), and would like to try building your own Posthaven theme get in touch at help@posthaven.com and we will get you started.