There's always that hidden gem. I don't know why, but we have metal framing in the roof. And ours is a 1997. We bought it in 2003 when it was 6 years old, it was in excellent shape, even had the sticker in the bathtub.
We've kept it up and replaced things as needed (except for the side A/C) because we never camp anywhere hot, but we kept the original drip pan and hose in case anyone wants to replace it.
For what i could get for it, I would never sell it since I have 10 acres to park it on.
We got hit by an oncoming wheel from a car going towards us on the way back from Yosemite one day, within 10 miles of our house, the insurance company totaled it, and we bought it back and got everything fixed except for a small crease in the passenger side top shell. It has a salvage title due to the buyback. It needs new tires since the tires are going to be 5 years old this year, only a couple of thousand miles on them, but we're planning on going to Wyoming this year so will replace them. No leaks right now, but you have to keep it maintained. We are older and I think our son might like to have the trailer and the truck if we aren't able to use it any more.
Don't be discouraged in your search. I think the older ones are pretty sturdy, and it matters a lot about how they are kept up. And no, ours is not for sale
I have posted a lot of things here on the board, about what to look for in a used TM, do a search, tons of info here. Do a search for "buying a used TM".
Good luck!