Git-buildpackage 0.5.6 in experimental got rid of it's pbuilder/cowbuilder examples and added Russ's nice git-pbuilder script. I'm very happy how this turned out, now building with cowbuilder is as simple as:
# Initially create a cowbuilder environment once
# Build the package
# At a later point update the cowbuilder environment with new versions
Or for another distribution:
DIST=lenny git-pbuilder create
git-buildpackage --git-pbuilder --git-dist=lenny
are now also supported when adding new changelog sections. Git-dch now detects new upstream version numbers automatically and bumps the version accordingly. In order to get this working I finally fixed the tag format.
Since the current version in unstable should get a chance to move to testing first, I've uploaded 0.5.6 to experimental.