Source: Toyota Creates the Ultimate Off-Road Sienna Minivan Monster The new Toyota Ultimate Utility Vehicle (UUV) combines two of the company's production cars to make one mean concept. Toyota began with the bare chassis from a Toyota Tacoma pickup truck, and fitted the body of a Toyota Sienna minivan over the frame. The body was made more aggressive thanks to the addition of fender flares and running boards. Those whom the Gods would destroy, they first move to Texas . . . or Freds House of Pancakes. Bob Wilson
Just realized that if the rear doors open, they would not be sliding doors. There's no way the sliding doors will clear the rear fender flares.
You wouldn't want sliding doors on a stump jumper anyway. After a few days in the woods, they wouldn't slide any more, for several reasons. This UUV looks more like a 'one-of' concept car than anything we'll ever see in the wild.