This is another type of kayak carrier being used today. This "rack" is actually called a "truck bed extender". It fits into a standard 2" hitch receiver. It's advertised to help carry kayaks, canoes, drywall or anything else that needs extra support.

Note: Before using any carrying device or system in which the load extends over the front, rear or sides of your motor vehicle, you should check for any regulations or restrictions. Motor vehicle departments or law enforcement personal should be able to verify any restrictions or limitations that could apply.
Thanks Dan for the photo.