Has anyone attempted this? perhaps starting a service and texting potential clients and getting them to OPT in?

any sites you can think of that offer this service either via one time payment or ongoing monthly payment?

Thanks!

You would need a "Premium gateway SMS Shortcode" they can run anywhere from $100 / month - $10,000+ per month depending on the amount of subscribers.

What an title..I thought for a few secs that yo would reveal your method.

Google for "Bulk SMS" services. They are out there but it is going to cost you and usually not worth it to do it unless you have a good opt-in list with some good offers. You really have to find a service out there to exploit and take advantage off but staying anonymous at the same since sending a text to the wrong person can easily land you a nice court date.