Hi Michel,
I'm not sure about the exact flow you are after, but Hippo Essentials has the concept of a plugin Marketplace [1].
First a short introduction on Hippo Essentials: this tool enables a developer to create a Hippo (Maven) project by adding plugins to your project. Each plugin has a combination of CMS components, HST components and (sample) content. When you follow the Getting Started tutorial you are using Essentials to generate your project.
At the moment, Hippo provides a set of these plugins from which you can choose. Hippo Essentials is envisioned to have multiple providers of the "list" of all features. This feature is not productize yet, but it would allow for 3rd party developers to offer a set of plugins for other developers to use in their projects.
For more details, also read [3].
Does this answer your question? If not, let me know.
Cheers, Oscar