Is there a slide and lock bracket available, like a camera hot shoe?

I want to attach removable headrests to bench seats in my camper van, there are no headrests at the moment, I would like to know if a slide and lock bracket exists, similar to the hot shoe bracket used to attach a flash head to a camera, you slide it on and lock it in place. I need to attach these bracket to the top of my bench seat, but it mustn't stick up too high as the chairs turn into beds with the back seats, so these brackets need to sit quite flat, a camera hot shoe bracket would be perfect, there must be something similar out there intended for a different purpose?