Arduino based SMS alert device

I'm looking for somebody to write the code to create an Arduino based SMS alert device. The key to the project is low power consumption as the device needs to be battery powered as it will be used in remote locations. The normal state of the device will be in deep sleep with absolute minimal power draw. It can be woken in 2 x ways. Firstly, when a float switch activates and 'triggers' a digital input. The digital input must remain 'on' for 5 seconds then a configurable SMS message will be sent to selectable SMS phone number. A retry structure, where messages are resent if send fails would be desirable. When the float switch returns to its normal state, a second configurable SMS message would be sent, again with a retry structure. Following the successful transmission of the SMS message, the unit would return into sleep mode. The second method of waking the device would be an input from a Real Time Clock. Once per week, at a configurable time, the unit should be woken to send a configurable 'Health Check' message via SMS, before returning to sleep mode. The RTC could be separate to the arduino, or incorporated onto the board as with the Seeeduino range. I have several different arduino boards at hand for testing the code, as well as a couple of different GSM modems which can be used by the arduino boards via serial connection. We can discuss which hardware is more suited to the task prior to commencing the project. Further options would be an advantage but not essential. Firstly, the option to send email alarms in addition to SMS. Secondly, the possibility of having 2 x float switches on 2 x separate digital inputs and the SMS alarm only activates when both 'on' conditions are met.