Well you beat me to it. I was going to post this tomorrow. I have the same issue. 2011 SR5 pearl white, 40 months in service, 39,000 miles. You can see the rust started underneath the paint as the paint is blistered from below. It has spread pretty quickly as I waited word back from Toyota.
Just heard from dealer on Friday after waiting 3 weeks for word if Toyota will pay or not. Since the vehicle is out of service they will pay half to have it repaired. Dealer said they tried to get full cost of repair and explained to area service rep that I'm EXTREMELY METICULOUS about caring for my vehicles so it wasn't a customer issue. The whole panel has to be striped and repainted after rust repair. Very disappointing and inexcusable. Not sure what I'm going to do next, will think about it for a few days. It will have to be fixed no matter which way I go. I understand the 4th gens had the same problem and a TSB was issued.
My warranty claims on vehicles that I bought new and are currently in my driveway or garage are the following:
2007 Honda Accord - 0 warranty claims
2007 Chevrolet Corvette C6 - 0 warranty claims
2008 Ford F350 Super Duty - 0 warranty claims
2011 Toyota 4 Runner - 3 warranty claims
Although I like the drive train, suspension, frame rigidity, and body integrity in the 4 Runner, I'm pretty underwhelmed and unimpressed with the body and interior both in quality of materials and durability. Just my 2 cents worth of the impression Toyota left on me as consumer when I make my next purchase. Not looking for a Toyota quality debate here.