A while ago I decided to become a bread & pastry producer and salesman. Since then, I've had a grand total of three customers. All of them bought in bulk, so it seems to me that trading on smaller scale is just too much hassle for most people. It involves a lot of walking and coordinating online time, so in the end it's easier to just make the item yourself. People randomly wandering to my place and buying goods is right out, because it's a rare event and I'd have to be shackled to my house 24/7 to ensure I'm there when someone who might be interested in trade strolls by.
So, what am I proposing? A new shop building. It'd look something like a market stand, and have at least a chest-sized double inventory (one inventory for items for sale, another for storing your payment). In there you could deposit items you want to trade away and specify what you want for a unit of each type of item you're selling (example: 20 cast coins for a loaf of bread). Then, a customer could come to your shop even if you're offline and buy items. With the theft skill, he could withdraw items from your shop without paying anything. If your shop is on claimed land this would leave a theft clue.
One problem with this type of trading is that it doesn't involve player interaction, so it could make H&H ever so slightly more single-player. Then again, right now trade is virtually non-existent anyway, so it wouldn't remove any existing player interaction. Still, to keep direct trade as preferred method, I suggest that some sort of wage would have to be paid to the invisible NPC that's running your shop. One cast coin per tick, ie 6 cic an hour or 144 cic a day, would be balanced, I think. When a shop runs out of these wage coins it simply ceases to work and can be "refuelled" with more coins to continue operating as normal. You, of course, can always deposit and withdraw items from your shop, no matter if it has "fuel".
Another neat thing would be ability to set goods to be automatically moved between the two inventories. So, for example, you could set your shop to buy bread for 15cic a loaf, and then put that bread in the "for sale" inventory at 20cic a loaf. Naturally, you should be able to set limit to how many items of each type your shop will buy.