Sorry, I do not know what an x/y-table is, so I would not know.
The application of it is such that a person is sitting in front of the arm - looking at its end, while it is moving. The movement is either in a plane in front of the person (like if you had a computer screen in front of you, but since we need to a range of +/-50 degrees right left and 20 up and 30 degrees down at a 40 cm distance, it would have to be rather large - thus too expensive expensive).
Also, we need the arm to move to and from 50 cm to 2 cm distance along a line from between the person's eyes and outwoards approx 0 - 10 degrees down. The apparatus (arm or whatever) should not bee prohibitatively expensive to produce, and should not block cameras standing behind the arm, acting as eye trackers.