So, you're trying to completely change the functionality of the "all products" page to make it be an independent page which only displays static content which you manually edit?

If that's your intent, why don't you just create a true dedicated page for that purpose?
The About Us contribution is an example of a static added page which could be adapted for such a purpose.
It would be a lot easier to manage that way. Plus, your visitors could access it as index.php?main_page=mygallery (or whatever you call it)