Giant Hot Air Balloon
Product Type: Hot Air Balloons
Manufacturer: Hot Air Balloon Guy
There are a couple of avenues that I know of to try to produce one of these
First, there were those guys in South Carolina that had a really cool giant hot air balloon along I-85. The cops chased them away eventually of course.
Then there is this site solar-ballons.com that seems interesting
Then there are these 30 foot diameter weather balloons for $99 from Amazon that look like they could have promise for such an endeavor