Begging and a good reason helps.
I think my limit is around 75 per campaign, then they opened another account for me when I ran out of those. That was when they liked me though, now they preferred I quit adwords :) I feel the same about them.
ps. my daily dig a adwords.
Just ask, and assuming your setup is reasonable, you should get it.
Yah, if you explain why you want them - they just raised one of my accounts to 100 campaigns after I demonstrated how many different types of products that client had to put in.
Yep - the key to successfully requesting more campaigns is to have an account in which the 25 campaigns normally available are organized and used in a highly effective way - by using ad groups to your advantage, and so on.
AWA