Unless someone hashes passwords with sha256d, which would be REALLY stupid, nope, ASICs cannot be used in that way.
Even still, ASICs used for bitcoin mining couldn't be used to find a password even if it was in SHA256d. IIRC, ASICs take the input variables, and internally increase the nonce range +1 and rehash until they're done, and then return the results. For a single Avalon or ASICMiner chip at about 300MH/s, this takes about 14 seconds. During those 14 seconds, you don't send any new data, the chip just hashes away. This design really doesn't work for password cracking.