Added link to the wiki for 75k Amex Surpass valid through 5/5/2014. New Amex T&C regarding churnability went into effect, as rumored:

"If we identify you as currently having an American Express® Card account, you may not be eligible for this welcome bonus offer. This offer is also not available to applicants who have or have had this product."

I am not sure what the first sentence means, but the 2nd one is pretty clear.