OK, so, talking with others in this forum, I got the idea to up the [trade_capacity] of some of the beasts of burden that elves use, so that I could get some more caged animals to purchase...
Turns out that going the blunt, graceless path of simply adding two zeros to the end of their carry capacity was a bad idea, as it wound up with something like 25 pages of inventory for the camels, and they would take longer than the time the traders would stick around the fortress to even unload the goods, making actual trade impossible. Even if I just looted it all, the sheer amount of CRAP these elves were trading was killing my frame rate down to the low teens. With just 6 pack animals!
Worse, using a little save scumming to go back to before the elves arrived, I didn't notice a drop in the camel's capacity after adjusting the raws... Apparently, what's in those camels is set before they actually arrive, but not before sometime in Winter, when I actually modded those raws the first time around. (I guess at the change to Spring?)
So... I did the only thing a dwarf COULD do... I turned on my atom smasher.
Well, turns out I mis-timed this - The second elf to come through (wanted at least one to get through) managed to see the bridge go down right in front of him, and got tossed by the bridge on the up-swing. This apparently dazed his camel temporarily, as these things do... but what happened next was unexpected. It turns out that these camels drop their trade goods upon being stunned... and because it had something like 300 goods stacks on its back, this actually caused a trade-goods tsunami!
A wave of bins of cloth, rope reed junk, wooden earrings, idols, and the like started flowing outwards from my atom smasher! It expanded the width of my hallway, fell down my atom smasher's trench to it's Hall O'Fun below, and threatened to drown my dwarves (and my framerate) with useless crap!
Fortunately, it didn't extend more than 10 tiles, and the atom smasher landed on top of 3 of the pack animals.
Still, that's 2 animals that dumped a veritable mountain of crap upon my fortress halls, and all I can do is set a dump site underneath my atom smasher to mitigate the problem, but with hundreds of trade goods, this will take QUITE a while to sort out.
Pictures of the aftermath (sorry for custom tileset, if it's confusing):