I am not a chemist, but it seems fairly certain that the possible permutations of substances that can be created to mimic banned chemicals is extraordinarily high. The U.S., for once, to its credit, is slower to ban these new marijuana-type substances, but it appears to be time to take some new approaches.
If "Tea Partiers" truly believe in their rhetoric, than the time has come to reel in the law enforcement agencies and to adopt an approach that saves money and minimizes possible harm from individuals ingesting dangerous substances. I am not convinced that the Tea Partiers in general actually believe their own rhetoric but there may be hope for the younger generation.
One of the classic unintended circumstances that came from banning alcohol for people between 19 and 21 in the U.S., was to make marijuana relatively more attractive to people who would have opted for alcohol had it not been illegal. I am not sure of the actual numbers, but by putting alcohol on equal footing with marijuana for people college age and under, the psychological effect is one of making marijuana use less of a fringe tendency, and we are seeing the results nationwide.
As the the self-absorbed baby boomers move on towards death, or at least Arizona, and away from their reign of terror of pursuing a 25 year "war on drugs" against their own fellow citizens, I am hopeful that things will continue to get better in the coming era.