Thanks Peter, there's some useful info there. I like the sound if the buck/boost regulator and there's some good looking automotive ones out there by the looks. Will look into combining one of these with some form of high voltage spike protection.
Shielded wiring for the CAS is a given, but what sort of filtering do you mean for the analog inputs? Do you just mean some capacitance filtering or something more serious?
The cases I'll start looking around for once the dimensions of the board are a little more finalised.
Thanks again!