This effort has been sparked by Dale's presentation at STIC 2012 (video).
The goal is to have a version controlled environment for cross-dialect projects. We do not aim to replace existing dialect solutions. There should be a convenient way to run development of a particular branch of a project in a dialect specific manner but be able to export the results into a (usually github based) common cross-dialect repository. The vision is that a cross-dialect project will maintain separate master branches for each dialect and rely on merging capabilities of the version control system to move changes between these branches.