Here's my elephanilla model rendered using my program:
As you can see, all the duplicated features (eyes, tusks etc.) don't seem to display properly. So far I've had no luck figuring out what's causing it.
It seems that the half facing away from the camera (that shouldn't be drawn) is being draw but the half that is facing the camera isn't being.

After a bit of testing, it seems to happen when I duplicate/mirror the features. If I duplicate with out mirroring them, they display fine.
Reversing the normals seems to fix it but messes up the lighting

edit: After freezing transformation and reversing normals, it displays correctly! Now I'm going to add some camera controls and then I'll try and make it a bit less picky.