I wonder if you could use a googlevoice number? That would open up a few other possibilities.
This is what I found:
It allows consumers to pay in bitcoin via any CoinPip Merchant POS from any mobile device with SMS functionality.
Also, this:
To beging using a 37coins bitcoin SMS wallet, mobile users simply need to visit
www.37coins.com and enter a mobile number in countries where the service has been launched. Once confirmed, the gateway can then be opened by anyone from any location and users can send and receive bitcoin from anywhere with mobile access.
I think it is possible to use with googlevoice, if you have a phone number.