Parallel chown over large file systems

I have a use-case where I need to migrate users from one uid/gid pair to another uid/gid pair.  Their files can be sprayed around over very large directory trees spanning 4PB of storage.  A standard "chown -R" would take quite a while to complete.

I've had a look at the Permissions Repair Job, however it does not look like it's able to alter the Unix ownership of directories/files.

Is there a hidden job that can perform this task... or is there a way of creating our own task within the Job Engine framework so that we can hopefully perform such a task in a quicker timeframe.

Essentially what I'm trying to avoid is the following:

find /mnt/5PB-fileSystem -uid 555 -print0 | xargs -0 chown 3333
find /mnt/5PB-fileSystem -gid 555 -print0 | xargs -0 chown :3333

Is there a way where the above approach could be avoided... as it could take months.