Great post!
I know a little about premium sms as we bill for europe via premium sms billing here at sex money.
As of right now I dont believe you can bill for adult websites or services via premium sms in the states.
Now with that being said sexmoney IS making webmasters money collecting cell Phone numbers in the same way we have collected e-mails in the industry for years. These are called Cell Phone cash Boxes and we are paying out 1.00 per confirmed cell phone number collected (2.50 for the 4th of july weekend). Here is a sample of our Geo Targeted Cell phone cash boxes you can use on any sites you choose
http://www.smutpreview.com/hostedboxes/