why no 3d homebrew games?

I was wondering where there has been a lack of 3D homebrew games? Is it because there isnt an engine made for it and is hard to code for or is it because there isnt any 3d artists helping out?

3D is considerably harder to do homebrew for than 2D. That's why you're far more likely to see mods for an existing 3D game (like Doom or Quake) than to see 3D homebrew. At least then you can work with a working engine and existing tools for levels and models. Unless you have something like Unity3D or Irrlicht or something similar, writing your own 3D engine is beyond the abilities of most homebrewers. Heck, it's beyond the abilities of most PROS too! Most game devs license an existing engine rather than do their own.

it would be awesome to play racing games with the 3d glasses on, although is 3d more of a novelty than anything else ?

I've looked at that a few times after playing ioquake3 with anaglyph 3D enabled... that's really awesome, by the way. Basically, you need to do two passes for each frame - render once with the camera set a little off to the right of the player position for one color, then a second time a little to the left for the other two colors. There are some docs about that on the net. I was thinking when I update the engine for Doom for Dreamcast, I'll work on adding anaglyph 3D to it as well. The DC should be fast enough to make "real" 3D Doom possible.

I've also been looking into voxel rendering. Someone asked about a 3D racer on the 32X, and while a polygon racer like VRD would be doable, maybe a voxel track with a few polygonal objects would be better. Voxel rendering uses the same kind of raycasting as is used for games like Doom, so it should be possible to do anaglyph 3D with voxels as well. I need to put together a demo for the 32X on voxels to get an idea of the speed to see if it's realistic. Anaglyph 3D might be too slow seeing as you need two render passes.