I just started building my Vex lifting device. This is the real rough stage of the build, But it will give you the idea of what I'm building. In the pics you can see the gearing and the Vex motor assy. along with the 2 slides that control movement. Now, I will have to cut the slides down to the correct length to fit inside the dome. I took a rough measurement inside the dome and it looks like I have about 10/11 inches to play with and so far this assy. is only 8 inches. I'm not sure how much lift is needed for the periscope, But it looks like the periscope is about 6 1/2 inches long. Once I get all the bugs worked out this should make a nice system. More to come.