Well, if by "usually" you mean other game engines, then yes. But in 3D Gamestudio nice detailed textures become a horrible contrasty mess as the camera pulls away from the model.

That mipmapping isn't supported for models surprises me (I guesss that's why I hadn't noticed until now.) From the little graphics programming I've done, implementing mipmapping was just an additional line of code. Admittedly, that was in OpenGL not DirectX (the graphics library A5 is built on) but I'm guessing it's just as easy, or if it is harder it isn't MUCH harder.