They might do one this December but I wouldn't be too obsessed about it. I used to be hung up on PR but then I realized that even if I don't have a high pr, I still rank high in the search results and ultimately, your ranking in search results is what's more important.
its always hard to predict G, usually there are 4 updates in a year, and there are only 3 this year. So i think last PR Update will occur on 31st dec or 1st jan as they did last year.
Just to be sure - as far as i understand it, the PR doesnt matter AT ALL. Well ok, it shows "backlink status" of a page in time of google PR update. But what really matters is number and especially quality of backlinks that you can see in google webmaster tool. Am i more or less right? I am not talking about SERPs, just about this "backlink status"...