Have scoured the internet for the following.
A keypad which can be mounted behind a sheet of glass with buttons which allows users to move the cursor up and down, left and right, and to 'click' a hyperlink. (equivalent of arrow keys and enter button).
Would imagine this would use proximity detectors/switches which could sense a finger through say 12mm of glass.
I've seen them as parts of expensive kiosk displays, but not for sale themselves.
Anyone know of anything?