I've also been in the trenches pre-Google. So many things come to mind to include in this response, it would be a mini novel.. but I will limit it to..
From an SEO perspective, running it within an iframe can present problems, most of which can be avoided by creating a sitemap for web crawlers that links to the non framed content.
Also you should know, I've stooped developing this script further, beyond version 22.214.171.124
(if you installed using Fantastico you do not have the latest version ) Instead I am focusing on something I call Dew-Dex, which I think will be cool as hell if can get some help with it.
Dew-Dex is essentially a CMS addon for Simple Machines Forum, somewhat similar to TinyPortal/SimlePortal, but maintaining the heirachical category navigaction DNPL provides. One feature that sets Dew-Dex apart from similar CMS add-ons is each category gets it's own entry and display template, so a category for websites, one for photos, one for articles and blog entries, videos etc, all of which can contain nested child categories.
Anyways, glad I could help and do let me know if I can be of service in the future.