Yet another new feature here at BCUK. The co-author function has just been improved - in addition to the two current types (normal and moderator), there is now a new type - guest.

A guest co-author may only make posts that are visible to other co-authors, or save a post as 'Draft'. So it could be used as a 'trial period' for new authors, to have more control over your current co-authors or to facilitate completely private discussions between you and your chosen co-authors.
the.blog coauthors

In addition to this, you can also display a blog's co-authors in the blog's sidebar. Just enter the Design Wizard in the usual way and drag and drop the module to where you would like it to appear.
designwizardcoauthor
By now you know our feelings towards your feedback. ;)