You can create repos using datatoolbox, but you cannot set rootPermission like the api supports:
http://repo.enonic.com/public/com/enonic/xp/docs/6.15.5/docs-6.15.5-libdoc.zip!/module-repo.html#.create
Also you cannot edit the permissions of the root node after you have created a repo.
It would be really nice to have either.
Do support this properly I guess one need a principal selector (role, group, user )
Original request from @ComLock