Try Vancouver !!!
I don\'t know about Visa extension in specific, but I got my initial H-1B stamping done in Vancouver a couple of years back - since then, I have suggested that place to a lot of friends, and they all got their Visas successfully from there. Some of them ignored the advice, and went to Toronto, since it is much closer (from New York City) - almost half of them got rejected there, and then applied again in Vancouver, where all were successful.
All the Best - Prashant.
