VIDEO-Market talk suddenly turns to specter of QE4

With no room to take rates lower, markets in near-free fall and worries building over a global recession, another round of easing would be the only monetary policy option left.

Read MoreThe Fed rate hike speculation is getting crazy

"I don't believe they're ever going to raise rates, because they can't do it," Schiff said. "People actually believe in the legitimacy of the U.S. recovery, they believe in the Fed's rhetoric. The truth is, everything has gotten worse. All the Fed did was blow a bigger bubble. All they did was interrupt the financial crisis."

While unlikely to take any specific action in the near term, Fed officials could start leaving a trail of clues in upcoming public speeches. No time would be better, for instance, than the Aug. 27-29 retreat at Jackson Hole, Wyoming, the very site where then-Fed Chairman Ben Bernanke planted the seeds for QE2 back in 2010.

"It's not about QE happening. If the perception of QE (happening) goes from zero to 18 percent, that's a huge impact," said Lawrence McDonald, head of U.S. macro strategy at Societe Generale. "Maybe even have one Fed governor, the most dovish of the doves, like (Minneapolis Fed President Narayana) Kocherlakota ... lay it out there. If one of them does it, look out."

For now, the market's deliberations have focused on the timing of rate hikes, and the current verdict is that the first one since June 29, 2006, won't happen until January 2016. The CME's FedWatch indicator shows just a 24 percent chance of a move in September and a 49 percent chance in December.

Read MoreFed may have just gotten a red light for rate hike

Economist Michael Pento, founder of Pento Portfolio Strategies and a frequent Fed critic, said the central bank has work to do before it could take viable steps toward another round of QE.

"For the Fed to go back to QE, there are two problems: First, they'd have to admit that everything they've done since 2008 has been a complete failure," Pento said. "Then, you have the problem that QE doesn't really affect fundamentals in the economy, it only affects asset prices."

Indeed, a recent paper by Stephen D. Williamson, St. Louis Fed vice president, said there was no evidence that QE provided the economic help that its supporters touted.

Read More'Forward guidance' didn't work, either

Also, similar easing programs haven't done much elsewhere in the world. Japan's aggressive QE couldn't prevent a 0.4 percent contraction in second-quarter growth, while the euro zone is barely above water despite its own efforts, with just a 0.3 percent improvement in gross domestic product for the same period.

"Sixty trillion dollars in debt and seven years of ZIRP later, anyone who thought this was going to be a smooth and easy transition to escape velocity is getting a rude awakening," Pento said. "That fantasy is shattering."