I've seen various posts in the archives that create a footer menu by creating widget space and the actual menu widget. However, is there any way to get the fully functional menu down there? I'm talking about the exact same thing as page/cats menus: hover colors, sub-menu drop-downs, etc.

Can you move the placement of where this function is called out in the main index file? Or replicate its code in the footer space?

I think you can just look at the page source, grab the code for the menu and put it in the footer. Two issues will be you will have to update it whenever you change the menu items and the menus may need to "drop up" instead of "drop down".

I think the plugin idea would be a simpler route.

I've gotten so used to just using either Atahualpa's native menu system or the generic custom menu widget that I haven't looked at menu plugins since pre-WP3.0. Any recommendations for a menu plugin that grabs from the custom menu feature and is customizable with color, font, etc.?

A quick search on wordpress.org brought up this one and this one. The firse one has been updated recently as well.