To put this in perspective, SecureLogix sells solutions that monitor your network and protect your VoIP/UC systems. While that creates a fairly obvious bias for a report like this, it also means that they do have great data from literally hundreds of networks where their tools have been deployed.
They've done a nice job packaging up the data, providing very readable charts, including solution diagrams and listing all sorts of resources at the end. The report is available now from the NoJitter.com site:
http://www.nojitter.com/sponsoredcontent/view/cid/3900003
You need to login to the site to download it today, but the folks I know at SecureLogix say that they will also be making it available from their own site in a few months.
Sure, you have to read the report understanding that it is written from the viewpoint of a vendor with an interest in selling security solutions... but regardless it is definitely a worthwhile document to read through. Kudos to SecureLogix for creating this report - and I look forward to seeing how it changes and evolves in the years ahead.
P.S. I found it interesting that the report talked about modems, which is something I actually didn't even touch on in the book and don't really think of as "VoIP" or "UC"... However, they certainly are components of the larger network security area of concern.