i believe i heard of this just recently, i think wal mart allows it, i dont know if it would be more than 2 days though.
ok quick google search, they allow it overnight but have no hook up for electric/sewage/water
http://www.liveworkdream.com/2007/11...-lot-camp-out/
http://bavatuesdays.com/the-company-store/
i wonder if you have to pay taxes if you do this?