no aftermarket 3rd rows available for 4Runner...
I did some checking a while back, and even the companies previously mentioned only make seats for Yukons, Tahoes, Suburbans, Expeditions, Explorers (new model). No 4Runner seats.
One thing the USA Today article neglects to mention about 3rd row in SUVs is the contact height. SUV's will have a higher survival rate and a lower injury rate because the bumper is higher than most vehicles contacting it, whereas most minivans have bumper heights the same or lower than the vehicles hitting it. Also worth mentioning, most SUVs 3rd row seats bolt directly to the floor (i.e. no frame for additional flex) where all minivans have seats that attach to frames.