It simply cannot happen, and if it does, I may just lose a whole lot of faith in Apple.
No, not because I'll be all uptight about having my device prematurely discontinued, but because if they start getting unpredictable with their iPad releases, they lose the hype. The queues, the buildup, nobody really knew the iPad 4 was coming until it did (some people still don't know, but that's another matter entirely...). Hype equals sales.
If they make it five in March, it will be without a new chipset (A7X) because they must debut the standard A7 first, probably in the iPhone 5S which at this stage looks set to stick with its usual Q3 cycle. This means they would have to update the iPad AGAIN in Q3 or 4 to include an A7X, creating another year with two iPad releases, resulting in them having pissed off everyone who bought the iPad 3 in the seven months before the iPad 4, the iPad 4 in the five months before the iPad 5, and the iPad 5 in the six/seven months before the iPad 6.
They must stick to this new cycle or they're going to create headaches for themselves. Three short lived cycles in a row could permanently kill the iPad hype machine. I don't think Apple is this stupid, and if they suddenly do become this stupid, we're in for sad times.