Publishing "filtered branch repositories" - workflow / recommendations?

Hi folks.

currently working on a project based on Moodle (the LMS that got me into git in the first place). This is a highly modular software, and I would like to maintain a bunch of "out of tree" modules in a single repository, and be able to publish them in "per-module" repositories.

So I would like to maintain a tree with looking like

  auth/foomatic/{code}
  mod/foomatic/{code}

where I can develop, branch and tag all the foomatic code together. Yet, at release time I want to _also_ publish two repos

  auth-foomatic.git
  mod-foomatic.git

each of them with matching tags and code at the "root" of the git tree, and ideally with a truthful history (i.e.: similar to having run git filter-branch --subdirectory-filter, but able to update that filtered history incrementally).

Is there a reasonable approach to scripting this?

Alternatively, has git submodule been improved so that it's usable by mere mortals (i.e.: my team), or are there strong alternatives to git submodule?

cheers,

m