What I would do for your project would be to use wire forms and cover them with parachute material and back light it maybe
That's what I was thinking. I was also considering 1/4 tubing-light, stuff and easy to braze.
But Like you I would have two large servos that could be a cost problem. I have considered air cylinders, but I really do not want to start air into the display.
Sounds like you have something impressive going on here.
Hey, we nned a thread on this and WE NEED PICS!