Further expanding on what Isaac suggested; in UBB.threads we've strived to make it easy for someone to hire a 3rd party developer to tune their site to their needs; you can add items to the <head>, header, footer via a textbox for those "includes" in the control panel. You can also add to the site styles through the style editor, and you can even craft your own BBCode via the BBCode editor.
Also, UBB.threads is commercial software, and as such we can only include additional scripts when their license allows it; which requires VERY SPECIFIC license types. If we where to a script which does not have a provision for Commercial Software, then it'd not only be a huge issue for the vendor (UBBSystems) but for the developers who included the scripts in the base code.
Now, I get that you have specific needs for your community, but these needs would be more specific to your site versus every install of UBB.threads out there, which is why we're pointing you towards options for customization.
