Has to ride folded down. I've actually seen one in person that was similar - dude had a ~21' blue water tournament i/o with a samson tower folded back on the trailer, two 2-seater wave runners up high. Pulled it with an escalade. He said it looked scary as hell but actually pulled really well and didn't feel like you would tip over going around every corner...

Saw one at Lake Billy Chinook last year that was the long version - room for 2 skis up front and the boat behind them. Probably was a 32ft trailer though... I think it was an Extreme brand trailer?