I am after an alarm system for our shed. It's been broken into before and stripped of all tools and I am refitting it out now.
I'll be installing a steel reinforced door and redoing all the window grates but I doubt I'll put much effort into that as a few grams of thermite busts through grates in seconds.
But my requirements for the alarm is:
1) The ability to send SMS's to more than 1 phone.
2) The ability to set limits, so say if only one sensor is triggered it won't send an SMS but if 2 are it will.
3) The ability to have both silent and vocalised.
Wishlist:
1) The ability to be silent but volume turned on with an SMS being sent to it.
2) The system sends an sms to the numbers given and it requires a response (sms response) and if no response it can send to a third number or notify a monitoring company.
I think that just about everything you want to do can be accomplished, but it is doubtful that you will find it all in a security alarm product. If I was you, I would look at some of the home automation type products as many have SMS connectivity and provide the ability to turn things on and off remotely using your phone. Most also have the "AND" logic that you will need so that two sensors must be tripped before an alarm is sent.
Do a web search on "home automation" + "SMS" and you can see what's on the market.