hmm if im understanding correctly...
importing into blockchain.info wallet would be quick..
if you imported into bitcoin-qt you would need to -rescan which takes like 15-20 mins on my pc.. perhps quicker on yours (bu hopefully not much, or i need a new laptop)
Is there a way to import a private key and sign a transaction with it sweeping funds to a new address, on the fly, with Bitcoind? Or, to achieve something like the speed of a Blockchain.info private key sweep, would you need to have the blockchain in a database and manually craft the transaction? Any input is appreciated.