I see in the owner's manual that my 2006 Land Cruiser is not approved for flat towing behind a motorhome. I have also researched this online and found that sometimes a manufacturer prefers not to recommend flat towing of their vehicles for warranty or liability problem avoidance.
My question is whether you know whether a Land Cruiser has some mechanical limitation that keeps it from being towed, or is it something else?
If it is a mechanical thing, is there a way to modify it for flat towing, or will I have to trailer it?

Don't do it... correct me if i'm wrong but because of the full time full wheel drive and the differentials you will mess up the drive shafts and transfer case buy pulling it with ANY of the four wheels free spinning on the ground.

Yeah, I couldn't find a reliable source that said it would be safe, but I got a lot of "I don't think so's" and "It might be okay—just give it try's".
So, I gave up on the idea and found a good trailer.
Thanks anyway.