That bit of info was in one of the Google patents over the last 1-2 years.
It makes sense, but it's nearly impossible to test.
I don't know if I'd do a 10 year renewal, but a few years maybe.
The way I see it, Google is trying to profile what a quality site is. The closer you get your site to matching that mysterious profile the better you are and the easier it is to rank well.
Most likely there are LOTS of things (like domain registration periods) you can do that, by themselves, won't make a bit of difference, but when you start adding them all up they begin to make a difference.
I read a lot to it effects the pagerank.I have a good domain(8 years old) and i buy it for 10 years.I havent an advantage on pr.My site is pr3 and it is a .com.The .net of it(same name) has a pr4 and it is only 1 year old and registered for 1 year.I tried and it is not matter or it effects too small.