Its not possible to have more than 5. And in my opinion its a bad idea to use 5 because you end up with at least 10 hits to the database to produce the page.

I recommend just use 1 on your home page and do layout inside the 1. For example if you look a the home page on this site it may appear to be 4 sections but it is really just one and layout is done internal to the html content.

We have some content templates that can help you get started with layout inside a single html content instance.

http://www.mojoportal.com/creating-content-templates.aspx

Hope it helps,

Joe