Here is a clock made from an old instrument cluster (1992 Seat Toledo).
Since it was a on and off project I don't have the step by step instructions with pictures. But the idea is pretty straight forward
Since the cluster was "as is" had to fiddle around to test if it does work at all. For some reason there was no pinout to be found (probably because of it's age). With a bit of luck and some reverse engineering the cluster was working of normal 12v supply.
Plan was to convert it to be powered from USB port (or a 5V power adapter). Since the MCU was using 5V already it was somewhat easier. Lighting is an LED conversion (since the 5v supply).
The frame is a custom ordered photo frame made out of brushed aluminum. Got the "deepest" possible, but still it was not deep enough. So it was necessary to shorten the elastomeric (zebra) connectors for the lcd.
After everything was tested and working got it into the frame with a switch for lights and a power jack.
Light is a lot more homogenous in real life than in the pictures :) Dimensions are roughly 10x10cm. Last picture is the original cluster.