Ok, here is my solution for those interested:
1) Since there isn't a way to display a unique Feature Slide on Categories or Posts (it's all or nothing on Cats/Posts), I had to abandon using the Cat/Post structure for my content and use WordPress Pages instead. So wherever a unique feature slide displays, that content is now a Page, not a Category or Post.
2) Quoting you, Bryan, you said that I, "could create a page for a category," but according to the WordPress codex, this is not possible: http://codex.wordpress.org/Pages
> Pages in a Nutshell > "Pages cannot be associated with Categories..." Sorry to put you on the spot, but if you know of a way around this, I'm interested.
3) Since I need to use the Cat/Post structure so that my client can assign content across categories, per their wish, I had to get Posts and Categories associated with Pages so that unique feature slides could be assigned to various content. For associating Posts with Pages, I installed the Inline Posts Plugin: http://aralbalkan.com/wordpress.
So in the end, Posts can be added to their respective Categories, and then displayed on my Pages, displaying a unique Feature Slide, per the Inline Posts Plugin. This works, though it is slightly on the cumbersome side. If there is a way to associate unique Feature Slides with Categories in future releases of this theme, it certainly would be on my wish list.