Generally you want fewer people with root access the closer you get to the root directory since the more harm they can do. So for example petsc/releases would only have Satish and one other with admin.

Which is perfectly fine and easy to set up now. Hell, if you *really* want to, just create the account: petsc-release(s) then the URL would be http://bitbucket.org/petsc-release/petsc-3.1