The best whistle blowing before the bubble popped had to be Peter Schiff telling a huge crowd of mortgage bankers they were about to lose their jobs in Nov 2006:
For those who don't want to watch an hour long presentation, you can watch a compilation of clips from different news show appearances, "Peter Schiff Was Right" http://www.youtube.com/watch?v=2I0QN-FYkpw
Peter Schiff fascinates me. He's had many right predictions and he's been making money off of these, all while telling the world exactly how he'll do it.
I don't think his investments are making much money. He bet on decoupling while the rest of the world looked to USA as the safe haven. He was right on some things, but didn't make a lot of money like some did in the crash. Like the hedge fund manager who bet on large mortgage defaults.
Peter Schiff has been screaming about hyperinflation for years and has been completely and utterly discredited.