Little chance of the price going up, I feel. Even assuming the Xbox One wins November NPD, it seems unlikely that the win will be a large margin considering both XB1 and PS4 had very good November bundles. Whomever wins November NPD, it's likely to be fairly close, and assuming MS gets some good press while winning, it's not going to do anything to close the gap if PS4 sold almost as well.
Bottom line, MS needs to keep the price advantage over Sony. Which will be a difficulty in the long-term because aside from MS losing money on the hardware, Sony can just as easily drop to $349 to price match if they feel the Xbox One is actually becoming a threat.