Arduino data logging firmware

We need firmware writing for an arduino which will sample data from two external SPI devices. Data will be logged and stored locally to an on-board SD card.
In addition there will be some bi-directional serial communication with our cellular device. This will give the arduino commands such as alarm levels, sample rates etc.
The arduino will monitor all inputs/memory capacity and communicate any alarms to the cellular device.
Spec. attached
We have a finished unit we can send to successful candidate to assist with development. We have an additional unit at our HQ to mirror the on-going testing.
We need a fixed price based upon completion of firmware as per attached specification.