I don't really understand what you're asking for, but I assuming you want help with the load time.
The problem is fairly straight forward. First, you're loading 12 CSS files, though these are done simultaneously, it is inefficient. You should combine the files into 1-3, or load only what you need for the page.
Now, the REAL time killer is those script files. 18 script files are loaded, one of which (jquery.mousewheel.js) has a 502 error and fails to load. These do not load simultaneously, but instead load in sequence. The first one (mootools-core.js) takes a full 1.5 seconds to load, and I'm checking from a T3 business line.
I understand not wanting to combine script files from an outside source. It makes it harder to update when updates are available, but it's also a major way to improve your load time. Another option, one you'd probably be more open to, is to use a script loader, such as HeadJS
. Script loaders, primarily, are designed to optimize the load of a larger quantity of script files. Mind you, there are limits to what any of this can do. If you are loading too much, there's nothing you can do that will fix it.
It is always best to create a system that does exactly what you need it to, rather than adapt another system. This allows you to create a CMS that functions the way you need it to, and is optimized to your standards. The downside is it is time consuming to set-up and modify when adding new features. You don't get access to pre-made extensions and, instead, have to make, or adapt, them yourself.
Here's a few articles on how-to optimize the load speeds for the CMS' I listed. Hopefully, I'm not blind and identified your website correctly, but it has been a few years since I worked with a non-custom-made CMS. ^^'
Joomla - 10 Tips for a Fast Joomla Website
Drupal - Why is my Drupal site so slow?
WordPress - 15 Easy Ways To Speed Up WordPress: Why Slow Page Load Equals Slow Blog Growth
I hope this helps. ^^
P.S. - I love the use of the iRobot model spin-off, just be careful, there's a great deal of similarity. ;)