I've tried  News Pro GK4 but am not happy at all with it, as I'd like something that has a scrollbar instead of tabs.

I have seen nothing that does this. Any ideas? For example, something along the lines of this: www.pbs.org/

 

 

Take a look at www.joomlabamboo.com/joomla-extensions/jb-slideshow-v3

There are several navigation and k2 options