I was thinking of using a dial with transparent cutouts for the ticks, then rotating a different color background behind them every twelve hours using a digital quarts movement so it would snap into place. Perhaps a timed GIF using an image list would work better though. You could have 2 dial images that change every twelve hours from an image list like this…

Of course, the GIF method would require UL. The hands would also use GIF’s like I normally do, but I would need to alter the image list for 1800 hours to 0600 hours with hands that are darker and have that phosphorescent look.
Here is a .xml file for it you can open in WFD. Change the hour of time with the “preview fixed data” feature to see it change at 6pm and 6am.
NOTE: I don’t use the new WFD beta with the array 100 touchspots stuff because it seems like the GIF features are missing and also it’s NOT backwards compatible with older version of WFD.