We are working on a project which uses svn repository as a central repository which has controlled checkins as patches, If someone wants to contribute to that repository they have to submit the svn patch.
But we wanted to use git as a repository for obvious reasons, so we have a mirror git repository for svn in github.
Its as simple as running the following command to generate a patch from git which is compatible with svn.
changes.patch can be applied on to svn repository with out any issues.
Origin of this command can be found @ https://gist.github.com/44537