I will just mention that Toyota could have just said, "sorry about the rusty frame, good luck". Yes that would have lost a lot of customers but I can't imagine this whole ordeal hasn't cost them customers and I can't fathom how much money. Out of the 1000's of frames that have been swapped out, this one person has a problem, most likely with a dealer who is not familiar with the process. I was just glad Toyota stood behind their product and fixed a huge problem they had, if not, I'd have been out two trucks now.
If the owner of this truck has older rusted parts on the truck, from years in the rust belt, it's not the dealer's fault that they can't put the truck back together with these parts. I had to replace my oil pan last March due to rust, was that Toyota's fault? It's a 15 year old truck and I live in NJ. I'm lucky the rear bumper hasn't fallen off. There is so much salt and other snow prep crap on the roads here that vehicles barely last 5 years without cancer.
What I'm getting at is, if you live in an area where they treat the roads in the winter, unless you are beyond diligent with upkeep, your vehicles will rust to bits and the parts attached will suffer the same fate. When I look to buy a "new" Tacoma, I'll be looking for an 05-08 with a recent frame replacement and around 100k miles. That truck will run another 100k and by then, the rust will have caught up on the rest of the truck and it will be most likely be beyond repair. You can't expect a vehicle to last 20 year when exposed to salt, no matter the manufacturer.
Skip the lawyers, skip the angry calls to your state agencies, pay for some new parts and drive your truck for 100k more miles, prob more since you live a in a relatively rust free vehicle zone now. Maybe you could offer to sell it to someone for the cost of repair. I think you might find some buyers...you could prob ask 3k on top of the repair price and still have buyers.
Sorry for the rant, I just don't understand the issues here...you can't make rusty parts new again.
-jorge