Well MacRumors do have a note about "IPhone plans" for Canada which lists SMS.
"- $60/month. 150 minutes + unlimited evenings/weekends, 400 MB Data, 75 SMS sent, unlimited incoming SMS
- $75/month. 300 minutes + unlimited evenings/weekends, 750 MB Data, 100 SMS sent, unlimited incoming SMS
- $100/month. 600 minutes + unlimited evenings/weekends, 1 GB Data, 200 SMS sent, unlimited incoming SMS
- $115/month. 800 minutes + unlimited evenings/weekends, 2 GB Data, 300 SMS sent, unlimited incoming SMS:"
Once again that is for Canada, according to MacRumors.
Rogers Announces IPhone Plans
I am sure things are different in Canada vs USA. They list the MG data breakdown, thats what they should do here, and allow Tethering.