There are whole bunch of stuff one can use if one is willing to DIY. I wasn't.
One of the easiest thing I thought of was to use a small air pump and hook up this air bulb thing. Just the tip end. Unlike solenoid or servo, you get to dampen the shock by actuating with air. There is a small air pump in all those automated blood pressure gauges suitable for this use. I wanted to avoid "kuchunk" type thing as it has a chance of transmitting this sudden shock to the camera body.
If you want to go the car parts route, Mercedes-benz vehicle from the 90s used pneumatic pump system for doors and trunks. (also fuel cap flap). A pump is hidden under the seat.