I am an Aussie expat doing sourcing in China. I can get homebrew kegs made in China from 304 stainless steel; a 12lt party keg and a 24lt brew keg with poppets, plastic base and top with handles for easy carrying; they are stackable and can be made reasonably cheap to allow for good profits.
Having been involved in making homebrew kegs in Taiwan for the Australian market back in 2004, i am fairly well familiar with them.
The new design will be able to be opened fully for cleaning and maintenance, unlike the Cornelius tanks that have limited access.
Can be fitted with “jackets" (great place for logos and marketing revenue) to keep them cool while on transport.
Can also make the replacement IN and OUT poppets for the existing kegs a lot cheaper than you guys can get them; all I need is decent size orders.
Also I have a design for a gravity fed spirits filter, removing foreign substances from spirits with carbon granules.