Carts and Wagons should be implemented. Although the 'wagon' exist, if nothing else, it should be able to serve it purpose as a movable container. A cart or wagon's main use would probably be to send out a dwarf to collect logs or rocks and toss them into there wagon. It would make it so they don't have to take painful trips back and fourth between stock piles. A wagon could hold quite a lot of logs/rocks, and than could be dragged back to a dumping location or stock pile.
Other things:
New stockpile- Wagon Drop Point
The wagon drop point would be made so that only wagons could drop off items in the location. They could be modified to accept anything that a wagon could hold and dump, rock, logs, trash, corpses, bones, ect. On the cart you could [q] it to collect *resource* and it would set out to pick the stuff up and return it to a wagon drop point. This would assure that you don't have a whole bunch of your dwarfs going about collecting things and instead have the one constantly going around, picking things up in the cart, and bringing it back. You could have multiple carts running at a time, and it would save you a lot of free dwarfs.
How to make:
It would be built in the 'b' menu. It would require resources from multiple places, much like a well. Wheels could be made in a masons workshop or a carpenters workshop. The carts body would be made up of 'cart sides' made in a masons work shop or carpenter's work shop. It would need three. Two mechanisms to function the opening of the cart for dumping, and two cork screws to hold it together.
Once built anyone with the hauling activated can be assigned to the wagon, and than told to pick up resources.