My Rietveld refactoring patch is now in, and we continue to discuss the Git-specific followup. (Thankfully, someone working on Mercurial support already did a lot of the hard initial work.) I've also written a more git-oriented subcommand which works like this: you run
git cl uploadto put a branch up for review, and
git cl dcommitflushes the current branch into a single svn commit using the description from the Rietveld review.