Logan... I believe this is something to do with coding in the footer of the forum with a custom intergrated CSS style code in it to keep the themes all on the same page...
That is if we're thinking about the same thing. 😉
You can change it in the User CP too btw, try linking to that in the footer... should work fine.
I've never worked it out so I'm sorry if I'm no help to you buddy. 🙁
I made a copy of portal.php and moved it outside my /forum directory, then I had to change some settings inside portal.php (it's just a URL change, anyone can do it), and then I'm done. My portal template is also custom, by the way.
You can either make a custom page by having PHP code take information from your forum and display it onto another extra page, there may also be a plugin for MyBB that you can do that.
Additionally, you can hire me and I will make a website homepage to look like your forum, however I will only do that for real cash and not FP cash etc.