Hi.
Here is a picture of my son and I when we where touring No Cal Universities.

My son Bryce has Cerebral Palsy and is confined to a wheelchair for life, as an added bonus he can not speak.
He travels in a special car seat made for quadriplegics, but it is basically a large child's seat with a four point harness.
Bryce is outgrowing his present seat and they don't make a larger one. The option most people use is to strap down the wheelchair to the floor of the van. I don't feel comfortable doing this as Bryce has so little control over his body that any accident would not end well and, well I'm just not comfortable with that option.
What I would like to do is instal a Sparco or other "racing seat". The seat would have to be raised off the floor and mounts fabricated so he would be high enough to clear his feet, see out and not be in danger form the side air bags.
I would also need to fabricate and install some sort of anchoring system to keep him strapped in properly that would have a proper shoulder mounting points not to break his back in a crash. Bryce already has to use a "sub belt" in his wheelchair and car seat or he will just slide out so he would need a sub belt in his car seat as well.
Any help on suggestions or direction you could point me in would be greatly appreciated.
Thanks
Steve