I provided art direction, layout and all the backgrounds.
Because we already had models for the characters, I was able to modify them in Photoshop to suit my needs for the concepts. When it came time to make the final film, I re-used the backgrounds from the concepts. I'm still amazed how close the CG team was able to get with the final products, my concepts almost look like screenshots.
Early Style Tests:
The clients chose #2, but I'm a fan of #3.
Some Odds and Ends: