Eh, by butchery I meant the menu where you can decide whether animals are available to be pets or not... which is also incidentally the place you choose to butcher them. But yeah, maybe assigning through the kennels would be a little more realistic - after all, they'd require some training and definitely some tack to cart things around.
Speed, on the other hand, would depend greatly on the animal's base speed. Which, as far as I know, isn't quite worked out at the moment. But it would make sense to use an elephant (quite slow, but capable of towing *MASSIVE* loads) to cart around lots of furniture, stone, etc., while using... pack dogs or something to carry around harvested food, or maybe a single bin or barrel. I don't know about you, but I envisage plump helmets as being kind of like apple-sized pumpkins. Which I'm pretty sure a dog or team of dogs could carry with ease, and quickly, too. Horses/Mules/Donkeys could haul around intermediate things like ore, bars, coin stacks, weaponry... that sort of business. That's just what I had in mind, though.
And after looking at the mine cart idea, that sounds like a pretty good way to organise it. Instead of making it instantly available once you get around to building a kennel, make it so that you have to build at least one mine cart (which could consist of multiple components?) to get it to work, plus a track for it to run on (you could have varying types of track, but they'd influence either speed or reliability - wooden tracks wouldn't work very well). This way, you could have designated trackways. Maybe it would even be possible to have bulk transport trackways and dwarf transport trackways. If there's a nearby cart with enough room on it and it's heading into a specific Burrow, the dwarf hitches a ride? That would be damn difficult to implement though, and maybe it's not enough of a gain to make it worthwhile. Besides the map area isn't quite big enough to make mass transit systems a realistic development.
EDIT: It could add a *really* cool element to sieges, reclaim mode, adventuring in old fortresses, and pretty much any kind of combat you care to think of. Just imagine a mine cart fitted with a ballista, or filled to the brim with crossbow-wielding kobolds
[ October 19, 2006: Message edited by: 20,000leeks ]