Number of Blogs: You can have as many blogs as you like on one account.
Apparently, the limit is against starting new blogs, not owning blogs. If you're like me, you'll note the limit when you try to Create a Blog.
But this limit, like many others, can be bypassed. You can setup more than one Blogger account, create more blogs under multiple accounts, and make team memberships of the blogs created. Setting up and teaming multiple blogs, of course, will be a tedious activity if you are going to setup 100+ blogs at one time, so plan the process and allow lots of time. Using multiple browsers or computers is highly recommended.
Just creating 100+ blogs, if you publish to "xxxxxxx.blogspot.com", won't be easy - remember each blog will require an available and unique URL. If you publish to your own domain, you'll maybe control naming there.
Either way, tracking 100+ blogs won't be easy in any case. Take a look at your dashboard, if you have any substantial number of blogs, and imagine trying to manage over 100 blogs.
And note that currently, Blogger, in the latest effort to mitigate publishing of spam blog farms, is using CAPTCHA screening and / or SMS verification, to block automated blog creation. If you plan to create more than one or two blogs in the same day, be prepared.