Manually migrate existing users into Bakery

I've created a module which allows authorized users to migrate existing accounts into bakery. It adds a field to the user's edit page with a 'migrate' checkbox and a field for the UID on the master. As well, it adds a count of unmigrated users to the site status, along with a message when it's possible to remove the module (as all users have been migrated).

This is relatively untested ATM as the staging sites for *.d.o aren't set up for SSO yet.

Would it be useful to add a list of accounts awaiting migration as well?