Stack Slideshow/Rotating Stacks
I don't know if this has already been suggested (or if it's possible), but what I would really love to see is a Stack or a Plugin that allows users to essentially rotate through a page worth of Stacks one-by-one. It would essentially look like a slideshow that would not automatically rotate. The user would choose when to rotate through the "slideshow".
The idea is that you could have a stack the size of a header and maybe the first slide is Stack with a single image or text (or even a Bannerzest). The second slide is maybe a Cooliris stack where the user could see all kinds of pictures or video. Then the third slide is an accordion style stack, the fourth is google map Stack, etc...
Basically, this would allow you to fit a whole page worth of stacks into one small area. The user could essentially see an entire website worth of information and never leave the first half of the home page.