Chassis strength of 20 -26 ft trailers with one slide

TurnThePage wrote:
When I was trailer shopping, I noticed that shorter trailers usually ended up with relatively stronger frames. That cheap I beam works fine for 20 or 25 feet, but gets weaker the longer you go.

I thought this may be the case. If they use the same cross section and same thickness it should be stronger. Is there anyway of finding this info out? Bert mentioned LCI, who else makes these frames? who makes the frames for the ORV trailers?