A normal car drive axle should work, my Honda civic axles have splines and pop in to a matching hole held in place by a snap ring, if you wanted a quick disconnect a push button with an indent ball like a socket set uses could work to hold it in place, keeping it clean when not in use would require a cover of some sort.
car drive axles also slide in and out a little to deal with suspension movement.
otherwise building a Gimbel would be needed.
Gimbal - Wikipedia, the free encyclopedia