Turtleshell is the pet project of graphic designer Joen Asmussen.
Over the years, it has been presented in various iterations:
» Turtleshell 2000
» Turtleshell 1998
The next version is being developed as time allows it. There is no timeframe for anything final.
You can follow development on this, and other projects at Joen's online journal, Noscope.