Thinking on it, it would be pretty difficult to implement a system like I mentioned. Or any system that doesn't use the current one as a rule-of-thumb. It would need to store all sorts of extra variables in pfiles and stuff.
Probably the best way is to approach it as mentioned previously: Take varying percents based on the number and severity of crimes committed.
Joe has been caught stealing: 5% of wealth (attempted theft)
Bob has been caught stealing and mugging: 15% wealth (attempted theft - 5% + mugging - 10%)
Jimbob has been caught stealing, mugging, and attempting murder: 35% wealth. (theft/5% + mugging/10% + attempted murder/20%)
Cletus has been caught stealing, mugging, attempting murder, and murder: 65% (...+ murder/30%)
Rush Limbaugh has been caught stealing, mugging, attempting murder, murdering, and high murdering: 120% (...+ high murder/40%)
Perhaps, if the criminal exceeds owing 100% of wealth, he must serve an extra day for each 10% over that is owed to the community.
Or would that be too ev0l?