Opera - creating a new contrib theme?

We've started to work on a new theme for contrib that is primarily designed to make it easier for a site owner to create a site with multiple stacked blocks (with background colors or images) that stretch the full width of the page. See https://www.backdropcms.org for an example of that style of site. 

This was not easy to do with a contrib theme out of the box. Opera hopes to address this need. 

While we are working on it, we'd love input on what else this theme should do or how can make a very flexible and useful contrib theme.

Let's also talk about creating contrib themes in general.