True, but the vehicle has to be engineered from the start for the spare tire location. Unless you want to use runflat tires, a compact spare like the Tucson, or sacrifice cargo space like the original Pathfinder LE and the Jeep Cherokee.
For instance, the first generation Xterra is the same basic vehicle as the first generation Pathfinder. To move the spare from the outside, as on the Pathfinder, to underneath, as on the Xterra, required moving the gas tank so the spare could go where the tank was behind the rear axle. The gas tank then went in front of the rear axle, where the Pathfinder had some room, but not enough. So they raised the back seat. This required raising the roof, which gave the Xterra its distinctive roofline. This illustrates the extent of changes required to move the spare tire.
I strongly believe that moving the current Rav4's spare from the tailgate to under the back end would require even more modifications, since it's a unibody rather than a body-on-frame. Putting it inside probably would eliminate the 3rd row seat option. I doubt there's room at all underneath on the shorter Rav4 sold in the rest of the world. Probably the Rav4 won't move the spare off the tailgate until an entire new design. Same with the Grand Vitara. Both have the main mufflers where a spare would have to go.
