authenticated user post comment/content as anonymous

I have a situation where all users must be authenticated in order to view, create content or post comments. There are some people that have a fear of posting in a situation where everyone can see what they are saying and I have been asked to give an option to "post as anonymous" when submitting content or comments. I was looking for a module that would still associated the user with their post but mask their identity as anonymous. This would give the content/comment creator the ability to edit their posts.

I started to build a module because I didn't find one in my search but before I go any further I though I would see if there were any pre-existing solutions. Also, it's easy to sometimes overlook an obvious solution that may already exist ;) I still want to show posted by info because 75% of the people are ok with their name being associated with their post but we want all users to be comfortable.

Thanks for any suggestions in advance!