I found this article on Enron and puzzles via econlog and whilst it is a long read it is extremely interesting.
Basically the information is in plain sight that Enron was in trouble.
Here is the student report that Malcolm Gladwell. A little bit of Google produced the pdf.
Perhaps a good rule of thumb is to always get the cashflow against profit and also profit against tax paid.
Whilst Malcolm mentions that Enron was unaffected by short-sellers, it was in the end. The short seller who spent hours checking 10Q and 10K filings could have ridden Enron into insolvency, keeping in the effect the whole amount which was short-sold.
Update:
I read the student report on Enron (ENE) and it reads like any other financial advice/analysis ie. slightly slippery, hedging bets, the short term recommendation was to sell. However the students remained convinced of Enron's strategy and remained neutral longer term.
They did in fact discover the possibility of earnings manipulation however chose to disregard it. In the reports word "no cause for concern".
Unfortunately any analysis now is tainted by hindsight. Enron was not some much a energy company more an "energy bank", where 88.9% of its revenue (but only 28.6%) of its income came from it financial arm. So like a bank it lived and died by the risk and cost of capital plus unlike a bank, there was no reserve bank to provide cash when the reserves are gone.
Have Fun
Paul
