Voyager

Documentation

IBM Redbooks

SG24-4630-00 OS/2 Warp (PowerPC Edition) A First Look
SG24-4639-00 OS/2 Warp (PowerPC Edition) Graphical Subsystem

We do have the first one digitaly, but not the second one. In case anyone finds that, let us know.

Darwin Documentation

There is plenty of documentation available about Darwin, a good start is Kernel Programming, which gives a nice overview about the design of the kernel.

Technologies to study

[1] - OpenGL interface for Cairo, so one could run Cairo directly on OpenGL, see Xegl for a diagram.
GNUstep.org

Design Decisions

Creating a binary compatible OS/2 clone may be tempting but is not strictly necessary. Important is the user experience. Which toolkit should be used for primary development?

GTK+
GnuStep (look at Apples programs to see what's possible. Yes I know Apple uses Cocoa not Gnustep)
other?

Dropping SOM for something better? Creating a poor mans SOM kernel isn't too difficult.