Er, git-svn is bi-directional? Targeted at allowing a developer to have a local git workflow that syncs up nicely with a central svn server? Is that the svn-git you're after?
No, the exact reverse: Hide away the brain-damaging GIT database system behind a proxy, so that I can (again!) concentrate on my job as developer.
Instead I have to spend at least one day every week as "version managment administrator" just to keep GIT from falling apart because of weird internal errors.
I will never understand why a plain user must deal with internal data structures (like db-indieces) of some tool on a day to day basis.