Thanks everybody so far.
I'm taking a multi-pronged approach so an aeromedical guy is rustling up some academic sources for me. I've contacted my local accident authority also.
I managed to google around a brazilian sites for lawyers and sites giving statistics relating to fatal/serious/minor injury classifications, but none I found gave me the injury types. There's also information here, but nothing as specific as I'm hoping for.
I hadn't thought of M-B. Will get in touch.
The HANS device was partially the inspiration behind the project. I had seen it around for years in motorsport and also didn't think it allowed enough movement until I was given a passenger ride in a touring car recently and was allowed to try the driver's spare. I thought it was a little restrictive for some types of operation but had much potential. I've found a paper on the known circumstances of use for various HANS devices and the G numbers are shocking.
What I've found so far is that lower spinal injuries (lumbar) tend to be from vertical compression loads such as rotary accidents and centre around where the spine has bent and the vertebrae have come into contact. Keeping the torso in place and supported during an accident event is most helpful there (ie sitting properly in a well designed seat and having your harness done up). Upper spinal injuries, (cervical) which tend to be more debilitating, tend to come from the unrestrained movement of the head and neck, the movement of which is relatively similar in vertical and horizontal accidents due to the anchoring of the movement in the torso. This is what I'm interested in, as well as those injuries that occur through the head striking an object and forming an axis, creating a severe bending moment on the spine or a Basilar Skull Fracture. I don't think a collar is of much value due to the compression of the material. Better than nothing, perhaps, but nowhere near as good as it needs to be.
What I'm really looking for is enough information to determine whether this injury type is common enough to get a return for further research.