I've contributed small-time to the Musicbrainz cd database, and I think they do it pretty well. New additions are automatically approved. Edits are accepted or rejected after a voting period (3 days, iirc). If nobody votes, they're approved by default; I believe (but am not certain) they are rejected in the case of a tie.
I think the beauty of this system is that it gives complete autonomy with no oversight to individuals dealing with obscure data that nobody else cares about, while more popular data is subjected to higher scrutiny.
This is more or less how OSM works now, except there is no waiting period. But undoing a recent edit is pretty straightforward, so there is a similar effect.
I may be a bit late to this post but as a contributor to both projects, I think the main difference here is that MusicBrainz is all about trying to prevent data deletions in favour of data merges, which will be resolved to the new object while OSM pretty much only cares about the look in the end.
So in OSM it's perfectly acceptable to delete an object and re-create it whereas in MusicBrainz deletions are very much frowned upon.
This means that you often can't really track changes to a single OSM object which would be pretty much necessary for implementing robust rollback behaviour.
I think the beauty of this system is that it gives complete autonomy with no oversight to individuals dealing with obscure data that nobody else cares about, while more popular data is subjected to higher scrutiny.