Here is an idea for you. Make your pistol grip out of acrylic, then embed a magnetic reed switch inside the acrylic. A sliding thumb-activated button with a magnet inside would close your switch when you slide the magnet over the reed switch.
I have used this setup on home made strobes and it works perfectly.
There are magnetic reed switches that are normally closed or normally open; you would choose the right one for your application.
Thanks for the reply! this sounds like a good idea! however, the pistol grip is detachable from the housing so i can attach a Pole grip, to get a much higher angle while shooting surfing and to make a long pole grip out of acrylic could prove fatal to my camera, also, could this switch work in 3 stages? Neutral> autofocus> sutter release...