I had a demo of Netgen Layouts a few weeks ago. This is a tool to manage the presentation layer of a backend content repository. It was originally built for eZ Publish, but Netgen is expanding it to other repositories.
A key point: you can back Layouts with multiple repositories, so it becomes a mash-up presentation manager for an aggregated content warehouse. This video is worth watching.
Now, you might say, “well, a bunch of CMSs do this.” Sure, but, remember, there isn’t one single CMS behind this. You can back it with multiple CMSs, each providing content in a different way and for a different purpose.
There’s value there.