Professions like blacksmithing and a job like being a merchant are two different things. On one side you have the ability to make your own equipment for adventuring. On the other side, you have the ability to be an NPC. I don't think it's wise to implement NPC-specific roles for players (and then program an entire system for other NPC's to come and browse whatever wares you're selling). It's just not practical.

I hope this becomes implemented but i don't think it will be.

sounds like a great idea, ive always liked the idea of a "merchant king" type character.
fable 3 was great with that
at the very least i hope mods will take advantage of the new economy system in skyrim, maybe we'll even be able to setup shops, buyout stores etc.

I understand what you're saying but I didn't mean you became a vendor. You're the middle man. So you buy from a vendor and sell to a vender somwhere else for profit. This involves watching the economy or even effecting it yourself(intercepting supplies, stealing all of an item etc.)

So that feature from Fable that no one used because it so much easier to just get money through other means?

Yeah so I can role-play a Lawrence character (Spice and Wolf).

That show made being a merchant sound so fascinating.