I think you've got the question turned around just a bit.
Anything with a metal case ought to have a three wire cord come with it. The wires in that cord are sized to the load.
Your metal cased equipment is attached to the rack with metal fasteners; it's pretty hard to do that without bonding the rack to the case in the process. So, having multiple devices mounted to the rack, each with it's own ground wire, is as sure a ground as you can get.
Using a power strip? Again, the cord to the strip ought to have a ground wire on it that is already plenty large for the power delivered.
Off the top ... if there is a 'problem' with static shocks ... that is proof of a good ground. Why? Because you are bringing electricity to the rack, and the rack is letting the static escape. Your solution is to stop carrying electricity with you.
For example, I once was called to 'fix' a desk that was 'shocking' the executive that used it. This gent had just bought a stylish desk chair, which had a heavy nylon mesh, rather than the usual cushioning. Well, nylon rubbing against his wool suit .... the man was a static factory.
Where there are static problems, the first step ought to be sure that there is some humidity - maybe 35% RH. Next, look for things like the carpet that might be making static electricity.
