Plastic "Dot" to Stick to Screen Cover. Very odd question.

This is quite odd and is not really an iPhone accessory, but I am using an application called Snatch that allows for the phone to act as a remote control.

I would like to stick a sort of "dot" to the screen that would allow my thumb to automatically feel the center and give it a reference point so I don't need to look at the phone itself. I have tested the concept out and it works fine, but now I need something more professional looking.

This dot should be clear and would look something like those dots you might stick to the underside of portable hard drive to act as a non skid surface and to raise it off the ground. But it should be relatively small, not bigger in diameter than a pencil eraser, and not be too too thick (maybe about .1"). It should have a contoured surface as opposed to a sharp edge.

Any idea of a product that might have something like this that I could utilize?

P.S. If you are wondering why I am doing this, it is have a central remote system that does remote control for media center, lighting, and to also have mouse and keyboard controls in one unit. While I have a nice $500 universal remote, it won't do keyboard or mouse controls.