Spectrum is again a Fluid design meaning there are no internal body layers. With this theme you have the main body background specified below:
Template.CSS - Line 3
background: #ffffff none repeat scroll 0 0;
Then all the modules flow on top within the body width parameters specified under the Layout Tab in the Template Manager. We generally do not use backgrounds like you have illustrated. The only Template I can think of that has something close to what your screenshot has out of the box would be Corporate Response as all the internal layers have backgrounds on them.
Technically you can get the layout with any Template but that would require some custom programming changes. Our support is for the core product, not customizations to the layout such as adding background layers that are not already present. All the background options we have available that are supported are in the Template Manager under the Backgrounds Tab. Here you can add backgrounds to any of the rows where you have content and it will flow behind the modules.