Rather than trying to dictate/engineer a "fault tolerant" economy, I suggest thinking more along the lines of "what simple mechanisms can be put in place in how the system functions so that participants in the markets/economies can make better decisions?"

Two things that I think are critical: * true transparency (e.g., look at the CDS fiasco ("look, it's insurance but it's not!" and the complete lack of reporting) * rate limiters (e.g., look at how much the recent volatility is due to the frantic rushing around, the reaction to all of that franticness, etc. For the physics enthusiasts in the crowd think of the propagation of supernovae through a given volume of a galaxy)

I really don't know. The stock market is somewhat balanced by bonds (and short selling?) in that they are alternative positions for people to go into in order to profit from changing conditions - but there doesn't seem to have been much of a way for the market position itself relative to credit becoming more expensive. I guess at the really abstract level you want independent agents to balance each other such that the sum of their positions resistant to change rather than reinforcing each other so they can all fail at once.

The same way you do it with computers: avoid central control. Central control is fragile, non scaleable (and promotes corruption when human beings are involved).