Several months ago when I was looking for a job I offered my services replying to a hiring thread email address. They never replied.
I live in SF, have 5+ years of iOS experience and worked at a chat company making their iOS chat interface for the last 4 years of it.
It came with a TN visa condition, but I doubt that is the reason why. TN visas have no waiting period, are pretty much a rubber stamp and $3000 in lawyer fees.
I got another job :/