Much like the "Hollywood Walk of Fame" but for businesses who exhibit exemplary, inspirational movements in the area of sustainability. Specific to large cities, specific blocks on the walk representing a company's ideas and concepts.
Make it visual. Make it something that can be seen by everyone, not just businesses who are involved. The Hollywood Walk of Fame is for stars who have "made it." It is a huge deal for actors and actresses, athletes and the like. So why not give companies the chance to "Make it?" To show themselves off to the world, but more importantly to the community in their given metropolitan areas. The Sustainability Walk would be a way to acknowledge, celebrate, and market the ground-breaking ideas that companies use to better our planet for future generations. For example, Denver would have their own walk, NYC would have theirs, San Francisco, LA, etc...The idea is to not just take blocks of concrete that have a company's name in it and say "congrats!", but instead, make this sidewalk a completely interactive exciting way to see what these companies have done to foster change.
So, a company who did something innovative with energy and lighting might be chosen to exhibit themselves in a neat way with lights and electricity under a plexiglass "block" in the walkway. Another company who has done something to create fuel made from corn might earn a "block" that has an ethanol-powered matchbox car on a track underneath the surface that people could walk on.
The possibilities are endlessly creative for what the "sidewalk" could look like. And the $40 million that will hopefully be raised will allow this to get kickstarted in multiple places. After that, once people recognize how cool the concept can become if thought is really put into how to represent each company and their contributions individually, the hope would be to receive millions more in donations. This would continually allow the sidewalk to grow larger and more unique as more and more companies are recognized for their revolutionary ideas in the world of sustainability. Not only that, but what company wouldn't like a little free marketing by having their name out there in public for all to see, as well as being named a recipient of their very own "block" on the Sustainability Walk?