You can create an mBox that 'redirects' to the versions of your homepage. You can do this by setting up separate experiences, and splitting your campaign based on a traffic split, or via some other metric.
For example, you can simply have one mbox that has two offers pointed to it. The first "offer" could simply do a default content - which would be your control.
The second "offer/experience" could simply be a java-script redirect to your alternative homepage.
You can then add multiple experiences/offers all posted to the same box that do similar tings to have a ABCD type of test.
I would avoid putting too much code in an mbox, as its loaded dynamically and can have performance impacts. I think a simple redirect to a static HTML page is a better way to go.