Decimal time apps keep appearing. Metriclock by Stotion was released on January 23 (55219) for $0.99. It is not only a clock, but also a "metric stopwatch and metric timer". The units have new names. Decimal hours/decidays are called "alkas", decimal minutes/millidays are called "zimits" and decimal seconds are called "ozzis", I don't know why. I have not tried it, but I see from the app store that it features a digital display with multicolored digits and a plain dark background.
The associated website is http://floint.com, which is in Flash, and therefore cannot be viewed on an iPhone. Doh! It's also difficult to view on my laptop, since it's a huge image which is larger than my screen, but I can see that it shows some pics of the app running on an iPhone.