Not directly related to PPC macs, but emulating desktop nvidia cards was and still is a tough task, so every pointer might help?
github.com
GeForce emulation (#562) · bochs-emu/Bochs@34ed054
This PR contains the current state of Vort's GeForce emulation. It implements basic support for three GeForce models. Most of the 2D features are present, but 3D is still to do. Several Windows...