Answers under questions
1. I've been researching SIM cards. They do have to registered, and plans are different -- more or less expensive. If you've more experience than I on what North American providers (esp. Canada) that don't gouge for basic service I'd be keen to know this.
Answer - This varies from service provider which GHL do not have any control over, it is up to you what package or sim card you decide to use.
2. More importantly, I'd be especially interested in know if you've planned to include a standard phone jack so we can use land lines to generate text messages. This would be a less expensive service to run in the long term.
Answer - different protocols, so no