Dallas to win the NFC (+250)
AND
Seattle to win the NFC (+250)
Those numbers are currently available @ 5Dimes.
So, if you bet both of them for the same amount, basically you have Dallas OR Seattle winning the NFC at (-133).
Is this a good bet? I have a hard time believing anyone else comes out of the NFC. I don't really like locking up money on a favorite, but it's hard to imagine any other NFC team winning.