Even the likes of Yahoo is PR9 I doubt many sites will be PR 10. Who has as much exposure as sites like Yahoo ranked first on Alexa, second on Compete.
Google does edit it's own services PRs. This is clearly demonstrated by the fact that Virgle (the April fool's joke) has a PR of zero despite thousands of backlinks. And the fact that almost every google service is PR7+ the day of launch. Even if there hasn't been a PR update. (This might just mean that they update it selectively, though)
Probably a joke. 2,000,000 Pound Sterling is peanuts to Google, and anyone who's going to put a link on their homepage. Think about it - for just 2,000,000 pounds, you get millions upon millions of people looking at your link everyday (have it placed prominently). Make it a snappy line people want to click on, and you have a dead server in a couple of weeks max. Though I'm sure most corporations divide load among several servers. Edit: It's also probably a joke because it will look too weird. Then again, it'd be all over the news everywhere.
I didn't expect Adobe to be PR10 - I would have guessed Wikipedia to be high up on that list. Is it really just the sheer number of links that means PR10 is possible?