As you know, authorship in the search results is a big deal. In fact, I am missing my face big time in the search results. But now, it seems that Google was testing Google+ company logos in the search results.
Here is a screen shot:
Note, this page doesn't have rel publisher code on it. It did however have a verified Google+ page and web site linked in the Google+ profile.
I spotted this via siegemedia.com and reported it on Search Engine Land last night.
I can no longer see this coming up in the search results. It worked for me last night.
So it is either a weird bug or a feature Google was testing.
Personally, I like it but hey - it is not my search engine.
Forum discussion at Google+.