[Spoke]

As with many new or complex features, this one is such that would require you to invest a lot of time tweaking and honing if you want it to be useful. The main thing to remember is that compared to real life, getting your hands on the materials to craft with is usually easy in a game environment. This being the case the other problem is that if you want a craft economy you need to have many times more users of the crafts than craftsmen, otherwise you will be left having to model the supply - demand scenario via NPCs. For this to work, you need an economy that allows you to gain income through other means, effectively making craftsmanship just another job you can perform and not a must-have.

I think the challenges in setting a system like this lie mostly in balancing it out with other ways to play the game. A game's economy is very different from a real life's economy mostly because of the limited number of people most games have playing, so RL economic models might not even apply to your game or maybe they will just produce different results. Bigger games like Second Life and such on the other hand, can use RL economic models easier due to the large player base they have.