Originally Posted by jsconyers
If you did find out their carrier, you could use the SMS gateway. What this would do would allow you to send an email and they would receive it as an SMS, and when they reply, they would reply as an SMS message and you would receive it as an email.
This should bypass any of Verizon's agreements or lack thereof. The only downfall of this would be knowing their carrier. Once you do, you could add that address into the contact's info and you're good to go.
I agree that this is a workaround. It is also a way to avoid texting charges entirely, at least outgoing, and particularly international texting charges. Alas, my need to use text is occasional and to a wide variety of people, who I don't have the time to individually track down. However, your solution would work great for someone with, for example, five international contacts they wish to text with regularity. Cheaper too.