This is an idea and a business that is awesome! Folks who are generally sustainable-practices-friendly but have never heard of permaculture tell me, 'I'd do that if someone converts my yard!' I'm wondering how many businesses are doing this, but it just isn't generally well known.
Speaking of converting lawns, I just found a link to a group in California that have created a CSA out of multiple folks' backyards. It sounds like something some people I just met want to start in the Seattle area:
http://myfarmsf.com/index.html.
Also, there is an amazing volunteer, non-profit group in the Olympia, WA area converting yards into edible forest gardens:
http://www.oly-wa.us/Terra/EFG.php.
Hm, maybe I'll eventually find a way to convert the swamp outside my patio that my condo association calls a "lawn..."