One thing for sure at this point is that it (STUXNET) was not created with the intent to profit but for destruction. With 4 0-day vurnabilities in it it would have gotten BIG TIME $$$$$ von the black market. Plus the code had 2 stolen certificates as well. From an "orginzaed crime/hacker" point of view it was a major, major waste of $$$ not to sell it.
Unfortunately, this is all conjecture. There's no proof of who is behind STUXNET.
It's also conjecture that the target was Iran. Many things use the controls this thing was built to attack. I'd look into what else can be attacked with this.
How many Siemens controllers are used in the US alone?
What if they all crashed within hours of each other?
Found these links today:
The Volokh Conspiracy VC scoops the security pros ? by two months!
Knowledge Brings Fear » Blog Archive » stuxnet: targeting the iranian enrichment centrifuges in Natanz?