We are just implementing crowd and somehow I missed the fact that an internal directory cannot have nested groups. I must have been reading about a directory representation of an external LDAP.
The primary reason we decided to switch to crowd was the amount of effort we must exert to manage confluence spaces, jira project permissions and SVN access in our varied environment. We have internal operational staff, developers, managers, then we have the same from our development partners (slightly different permissions), and yet a different set of permutations with customers (they use all of the above as well).
We have only been using the jira database for authentication (with the exception of SVN), and when we decided to add fisheye, bamboo, and crucible to the mix it was definitely too much not to use crowd.
I see this on the roadmap for 2.0, but I'm hoping that my vote and this comment may be some fuel to expedite the implementation sooner rather than later.
Even if this might be available as an unsupported patch, we would be happy to try it out.
This has been implemented for both Internal Directories and Delegated Directories.