Goes to show you could get any size you want.   Shown here is is a true 33 footer - 3 foot longer than the 30 foot Sovereign of the era. The Sovereign didn't even go to 31 feet until 1969. 34 feet was finally obtained in the 1990's. Even had a unique custom window arrangement over the aft bed that utilized a pre 1958 Hehr window style (above). Uses the Henschen Dura-Flex axles introduced in 1960.  S/N is 33 S 0 108. 

Only trailer I know of this length, but the 108 sequence number leads you to believe there are at least 7 more out there...

 

The other examples shown are monster 35 footers!

Makes you wonder what California was thinking that year.