Platforms like GitHub and GitLab should support a workflow consisting of series of patches instead of a specific commit on a particular branch. They could probably even show pull requests from email in their interface.
It could be as easy as adding some toggle to enable sending a patch series when you push to a specialy named branch, to relevant people (mentioned in the patch message for example, via Cc: tags).
Something like:
git push master:email/v1
Email/v1 branch would not be created, it would just be a virtual target branch name for this functionality.
You can easily make a git hook script to do it with regular ssh/http based git hosting.
