I highly doubt that. maybe $299it is good if the have inventory then go ahead and update the new iPad with A6.
with existing supply chain issues (and demand for iPhone 5, iPod touch) I do not see that happening.
also it will piss of lots of new iPad owners.
A6 Will improve performance and if it improves battery life we might see lighter and thinner new iPad.
but at month of Oct, it is too risky to change your product line before the holiday.
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then it will priced at $499, you want that?