For some reason, the rise of the internet also birthed the specter of the cancelled election.
The opposition has speculated wildly about it since Clinton's first term, but it didn't happen with either Clinton election or either Bush election. Bush's third term didn't happen either. Obama will either be elected for a second term or he won't, but there will be an election.
Elections are managed at the state level. So you are correct that the Fed cannot simply “cancel” the election.
However, we have already seen the contempt this admin has for state law. It is not hard to imagine a scenario in which the Fed mandates “postponing” the election, and sending troops in to non-compliant states to enforce the mandate.
The media would support it, and would report that Americans also supported it.
Just sayin. If it were going to happen, this would be the President that would perpetrate it.