This is pretty much a rough sketch mostly to show the general layout
I had in mind.

My primary idea was to have a more horizontal layout like the previous 
design, but to have the buttons at the footer rather than in the middle 
of the page, so the rest of the content would appear in the middle.
I just used a bunch of images in the folder for placeholders, but I 
wanted to have the content switch within a central div. Once we have more
content to each of the buttons, I figure we could have the whole div 
animate so it looks like its scrolling horizontally to another page while
the header and footer stay the same.

I also looked into horizontal scrolliing, which I wasn't sure if we could
use since we need to stay compatible with older browsers. I thought we could
maybe have the background change depending on which button is clicked,
or doing something similar to oneiota.com's sidebar, where we'd have 
some button animation (leaves that rotate or "grow" or something) and 
then have a scrolling effect on the page. Here's some links I looked at
for inspiration on cool minimalist scrolling or switching the background:

http://www.oneiota.com/ (Really like their minimalist sidebar, maybe we could do something similar 
 horizontally in the footer with leaf icons)
http://tympanus.net/codrops/2010/06/02/smooth-vertical-or-horizontal-page-scrolling-with-jquery/ (like the general idea but 
not too thrilled with the scroll bar on the bottom)
http://jsfiddle.net/M2LmH/ (rotates backgrounds but could be switched to switch backgrounds on button click)