It seems I've been working on a very similar Drush tool, https://bitbucket.org/davereid/drush-patchfile since the beginning of this year. I'd love to collaborate where we can to make one awesome Drush patching utility!
Corresponding drush-patchfile issue: https://bitbucket.org/davereid/drush-patchfile/issue/13/collaborate-with-the-bandaid-project