EVGA presents its Analog CPU Speed Meter at CES 2011. The speed dial indicates your processor's clockspeed, it uses a GHz scale that starts at 1GHz and ends at 6GHz.
Might be a nice addition to a steampunk case mod.
By the looks of it, the device fits onto the case with its dial facing the user, latched onto the case using the side-panel screw. It connects to the system probably over the EVBot interface. Another possibility is that the device connects to the motherboard over USB (front-panel) headers. The meter's dial uses a GHz scale with starting unit at 1 GHz, going up to 6 GHz, with no distinct divisions between.