State of the art re: group default privileges

I'm running into this exact situation:

http://www.postgresql.org/message-id/CAG1_KcBFM0e2buUG=o7OjQ_KtadrzDGd45jU7Gke3dUZ0Sz92g@mail.gmail.com

We really need to be able to have a group of developers who can create
things and modify each others' stuff[1]. Is it still more or less
impossible?

The workaround that comes to mind is a script to enumerate all
"developers" and then set the defaults one at a time. This breaks
however when we add a new developer -- he can't access any of the
existing stuff.



[1] WITHOUT making them set their own permissions. For the sake of the
discussion, let's say they can't be trusted to get it right, or more
likely, don't feel like it.