Yes, there are a number of ModeShape users that are using it to store configurations and UI information. That information is likely naturally hierarchical, and probably a really good fit for JCR (meaning it would be easy to define a repository structure).
Whether or not ModeShape is too heavy-weight for your use case and application depends on your perspective. JRE-wise, it won't take up many resources. But ModeShape 3 depends on Infinispan, which can have a large number of dependencies, depending upon how you want to persist the information.
I suggest that you give ModeShape a try with a simple proof of concept and see for yourself.