I had a buddy with an old Newmar London-Aire fifth wheel from around 1987. His kingpin was about 2 feet behind the front of the nose cap. NO WAY in the world to tow that trailer with anything less than an 8' bed.
Here's a link to the brochure for that year. You can see an old photo of their fifth wheels about page 5 or 6:
https://newmar.imgix.net/wp-content/...ondon-aire.pdf
Also, take a look at the "improvement" in advertising from "back when" and today's "sell to the innocents who don't know any better"...