Greetings,
Because of recent developments that made it possible, I tried my hand at making a new vending stand that trades items for items, rather than items for coins. I'm not sure how well it works yet, nor of its utility, but please try it out.
It works pretty much like the current vending stand except for the price setting. You set the price by clicking the "Change" button and then point out an item in your inventory. Upon doing so, you will be presented with a little dialog box for choosing the desired item type, the quantity of it and the required quality. When you choose a bar of steel, for example, you will be able to choose whether to require steel, hard metals, common metals or any metal.
It's an experimental implementation, so it may well be buggy. Furthermore, Jorb has had no involvement in it, so there's no new graphics for it.
Enjoy!