Actually, I think Cheney said he didn't figure the Iraq war would go on more than sixty days, tops, and it would be financed with Iraqi oil revenues.
Note - after looking around, I see 'twas Rummy who said he didn't think the war would go beyond six months, and Wolfie who made the comment about the oil revenues.
Though Cheney does have his own fair share of misfires. There were the definite ties to Al Qaeda, proof of WMD's, the 'last throes' of the insurgence, and so on.
Here's a goody, though, one he was right about. "Once you got to Iraq and took it over, took down Saddam Hussein's government, then what are you going to put in its place?" Mr Cheney asked. "It's a quagmire if you go that far and try to take over Iraq."
That was in 1994, after the first Gulf War.