Here is a video that we made a few years ago as a product video for our double decker pontoon boat. AKA the Party Barge. Rolling Barge makes Party Barges and Pontoon Boats on a custom basis only. We are not able to sell these as a kit because there are so many different options. Accessories such as bathrooms, slides and different sized motor option are all available.
As far as sizes go there really is no limit to how big we can make them, however if you want to tow it down the highway 30 feet long and 17 feet wide is the largest size. A Party Barge of this size would give you a maximum weight capacity of around 4,500 pounds or about 25 people.