One company that makes these also does gargantuan custom playhouses. Um. Yeah.
My mom's in the DC area, where housing is outrageous; I can't imagine what the housing market must be like in Southern California, for the prices of these playhouses to not seem utterly insane. There are places in the countryside -- hell, in small towns! -- not far from here here where you could buy a house for less than the price of Tumble Outpost.