Fer tha October CCC we're bashin' together a few Vendor Carts.
We'll be starting with them as placeables. Each will have off and on states - off will be empty, on will be stocked. Builder's can script the state to flip when a store is empty/stocked.
Later, we'll rebuild them as creatures. Builders could then script the Vendor to follow behind the cart-creature as a poor man's attempt at pushing.
Finally, we'll rebuild them as mounts. The issues there are that a new pheno will be needed and a modification of the mount scripts. Also, as a mount is really just a tail, the cart will have to swivel to the side whenever the vendor stops. Otherwise, when the vendor turns to face the PC, the cart will swing over on top of the PC.
Well, thet's enough ta go on.