My fortress finally got too damn slow, and so I abandoned it. Intending to go loot it for cool weapons and armor, I start as a dwarf from the parent civ (this civ has but a single site, which may be relevant.) I'm immediately greeted by fifteen wagons scuttling themselves. Each scuttled wagon left behind a pile of logs... and everything I had traded home over the years! There are piles of ownerless golden goblets encrusted with gems!
There also appears to be everything the caravan brought that I didn't take, because I know I never gave them any barrels yet I've found a masterfully encrusted (Twice! With aluminum and Native aluminum!) one here. The caravan animals are also about, laden with goods, though I don't know how to get them away from the animals.
The real tragedy is there isn't a damn thing for me to spend my newfound ridiculous wealth on. I should come back as a human; at least then I could buy armor that would fit.
Looking at some of this stuff, I'm not sure where it came from. Some of these scuttled wagons had steel bars, which I never would've traded away and buying everything I wanted was never a problem. Perhaps caravans are generated some time before they actually show up?
Aside: the Queen just punched a mountain goat to death, now I'm sad I didn't keep the fort going a few more seasons to have her show up.