[petek]

One thing to keep in mind with vacuum is that the forces you can create are rather limited unless you have little leakage or very high vacuum generating capacity. Recall that a perfect vacuum is by definition -1 atm relative to ambient pressure, which is approximately 14.7 psi, so to exert a lot of force, you need a lot of area, which in the real world usually means you have a lot of leaks. Assuming your vacuum storage tank and evacuation system are legal (I haven't looked into that aspect), you would probably need a pretty large tank if you plan to grip a leak-prone surface like the Trackball.