I doubt Google assigns PR manually to any site. I don't think they would like to waste a resource checking out 200-300 odd sites and assign them PR10. I bet there is an algorithm! And then again PageRank is a Google thing and doesn't really mean anything in the business world. Or does it?
Waste a resource... or earn some cash from a 10PR site owner. We don't know how their algorithm functions, and we can't know whether it has been set to calculate PR up to 9 and then leave the highest rank to the Google expert to assign manually or not.. Business is business afterall
I think statcounter.com is a PR10 and they're selling links spaces. If you've got deep pockets, then go for a link or two.
generally PR 8, 9 and 10 will be sites that are run by big corporations and businesses. PR 7 is the highest I have seen from a fellow Internet Marketer.