The best tent trailer was a "Camper DeVille" all heavy guage aluminum box, steel frame, oversize leaf springs and 14" wheels. It did float! Doubt you'll ever find one, they were built in the early 60s and went out of business in the mid 60s! My dad had a camping supply and we had two of them, probably not a dozen made and ours are long gone, you're probably drinking beer out of them by now. The old Apache mentioned above was the leader in the market at the time and the DeVille was a much better trailer and cost a little more, the Apache had smaller wheels and wouldn't track like the larger wheel fully loaded. But, if you can find an old apache the box would be good to start with.
If you want the Rolls Royce of tent trailers, I'd suggest you have it built. That's the only way you will get exactly what you want, as tuff as you want and it won't be that much more, if any more (good chance of being less, IMO) than anything you can buy that is set to the demands of the market.
All trailers manufactured are done so to meet the greatest market demand for the type, shooting out to the demand in the market witin a price point, so you'll never get a manufactured off the shelf unit that will be the ultimate in all respects, they have to play the price-demand game.
That's a great marketing video up there but I really doubt there was anything inside it......we can do that when toilets, sinks, pumps, stoves and cooking pots are made of foam rubber.....LOL