I just tried using the following in the head section of a page :
<link href="https://plus.google.com/yourid" rel="author" />
Mind you that in the footer I also link to the g+ page with a rel=publisher as well as link my Facebook and Twitter accounts for the site as well.
Here is what was returned when using the rich snippets tool :
linked author profile = [plus.google.com
google profile = [plus.google.com
author name = Widgets .
Verified: Authorship markup is verified for this page.
Please note that this does not guarantee that your profile will be shown in search results.
linked author profile = http
linked Google+ page = [plus.google.com
Verified: Publisher markup is verified for this page.
From the above results it appears there is no problem using a page as an author nor using it for both author and publisher on the same page.
Now, does this conform to Google and will this end up biting me somehow is the question?
[edited by: Robert_Charlton at 6:37 am (utc) on Sep 5, 2012]
[edit reason] delinked twitter example url [/edit]