Are you kidding? I started working on my holiday campaigns last week.
25 is the default max; you can get more if you ask Google and can make a good case for it. I have some accounts running over 100 campaigns now.
This looks like a great move on both the advertising and publishing side. AWA - I think a webinar on this would be a good idea; it's been a while since I did much with site placement, and I could use a refresher, and I'm sure there are lots of people who never messed with it.