Yeah, I figured that would be the case.
Sadly, however, the staff isn't that co-operative when it comes to forwarding messages from users to users. The first e-mail reply I got from the WordPress.com team was:
"I'm sorry to say that we are unable to give out contact details for our users, you'd need to leave a comment on the site in question to see if the owner would be willing to transfer the blog to you."
After I had explained that I can't leave comments on the site, another staff member replied to me, saying:
"I'm sorry, but deleted or inactive blogs cannot be restored or reused. Please check out this page to learn more about deleting your blog: http://support.wordpress.com/settings/delete-blog/"
When I continued to explain that I just wanted to contact the owner in hopes that s/he would be willing to transfer the blog to me, the staff's reply was:
"I'm sorry, but we're not able to transfer that blog for you."
At this point, to be honest, I started to feel a bit frustrated by the answers they were giving me. First, they suggested leaving a comment to the blog, which just wasn't applicable. Then, they started talking about the behaviour of deleted blogs, claimed (erroneously) that inactive blogs couldn't be reused, and even told me how to delete my blog, which I think was somewhat irrelevant. After that, they told me they couldn't transfer the blog to me, but that wasn't what I was asking for, I asked them to contact the site owner for that. So I asked them to give me a clear answer:
"By this, do you mean that WordPress.com staff can not contact blog owners?"
To which a third staff member replied:
"Correct, we are unable to contact users on the behalf of other users."
Because of policies like this, I would prefer that there was a way of directly contacting the blog owners without involving the staff in the process, but there isn't, so I just can't reach the user that owns the blog - end of story.
Bottom line: there is currently no way of contacting the owners of empty WordPress.com blogs.