Having a multi topic blog does not have to be that hard with subdomains.

So you dont want to have a niche blog where you focus on one topic. You have so many things to say but you really dont want to have a mixed up blog because you know niche blogging makes more money online?

Here is what you can do:

Take all the categories of your blog and make a sub domain for each of them. Then start a separate blog for every category you want to blog about. That way you get to blog about everything you want and you have a bunch of separate niche blogs making money all at the same time.

What you can do then is start a stream or feed where all the blogs meet together on the main page.