Raphael Hertzog:
Up to know I was rather thinking of designing a new tool "vcs-buildpackage" but maybe I simply want to create new source formats "3.0 (git2quilt)" or "3.0 (bzr2quilt)" and extend the dpkg-source integration in dpkg-buildpackage.
That only works if you use a rebase workflow in the VCS, not if you use a merge workflow. Personally, I find merge workflows easier to follow, since you can track the branch back through history properly. Unfortunately, such a workflow can't easily be translated back into a set of patches to apply on top of the current upstream.
-- \\// Peter - http://www.softwolves.pp.se/