Guilt (Git Quilt) is a series of bash scripts which add a Mercurial queues-like [1] functionality and interface to git. The one distinguishing feature from other quilt-like porcelains, is the format of the patches directory. _All_ the information is stored as plain text - a series file and the patches (one per file). This easily lends itself to versioning the patches using any number of of SCMs.
Tarballs: http://www.kernel.org/pub/linux/kernel/people/jsipek/guilt/
Git repository: git://git.kernel.org/pub/scm/linux/kernel/git/jsipek/guilt.git
The code is licensed under GPLv2.
Of course, contributions and feedback are welcomed :)
Josef "Jeff" Sipek.
[1] http://www.selenic.com/mercurial/wiki/index.cgi/MqExtension