I think an ancient economic model is the best idea. We should take into account the unequal value of the labor of individuals, of course. Toady's current system, in which the dwarves are paid out of a credit system made good by the assets of the government, is probably the most solid and scientifically sound system that can exist. I think the flaws in it are really simple programming flaws, with a very small number of actual conceptual problems.
The reason for my position is that it is not subject to the corruption of a real government run by human beings. Favoritism, greed, deception, and just about any other corruptive vice present in a real society would render such a system highly impractical. In an ideal world, such a system would be truly perfect and suffer from no inflation or vice, and a free market would ensure a balanced distribution of goods given free will to take initiative and fill market gaps on the principle of earning profit for your labor.
In the end, I think we come upon two very important issues:
1) DF is a socialist or communist world, in which an authoritarian power dictates the jobs available, the work permissions, etc. There's no place for any kind of freeflowing economy based on supply, demand, etc.
2) A realistic, modernized, or complex economic system given the conditions above
A) serves no practical purpose beyond providing bragging rights about our beloved DF,
B) would be incredibly convoluted and difficult to create,
C) and thus logically is nothing but a burden to the programmer, processor/game speed, and players.
I really think that's about all there is to be said on the subject: The simpler, the better. If dwarves work, then they eat, drink, and sleep in relative (to their industry) comfort. When our options for society become more complex, then a more advanced economic model might have a real place in DF.
However, for those simply interested in economics and its possible applications in DF, it's still fun to discuss, dispute, and theorize. I'm just being intensely practical, and felt the need to point out the practicalities. Also, a need to point out that logically speaking, implementing a complex economy in DF as it now exists would be in fact a very undesirable thing.