Hi, I've released a 3D engine called Wire3D (
http://wiibrew.org/wiki/Wire3D ). In terms of a Wii homebrew pet project I think it turned out to be quite nice, however in comparison to engines on other platforms it's still very rudimentary. All the rendering basics abstracting the hardware are there, so it's a matter of adding high-level features to make the project more useful and developer friendly.
Since this is more than I can handle in my spare time, I'm looking for people to join the project. If you know C++ and want to participate, please contact me (antibyte at gmail dot com). From simple features, like a skybox, terrain or a particle system to more complex features like a gui system or adding a platform independent sound lib, there's a lot of stuff that could be done. Or you just contribute your own ideas. Either way I will help realizing them.
If you have any questions, contact me or post them here.
(P.S.: sorry for posting this in the wrong section at first)