What options (in C# with XNA) would there be for texture usage in a procedural generated 3D world made of cubes to increase performance? Yes, it's like Minecraft.

I've been doing a texture atlas and rendering faces individually (4 vertices per face), but I've also read in a couple places about using texture wrapping with two 1D atlases to merge adjacent faces with the same texture.

If two or more adjacent faces share the same image, it'd be quite easy to wrap in this way reducing vertices by a large amount. My problem with this is having too many textures, swapping too often, and many image related things like non-power of 2 images.

Is there a middle ground option between the 1D texture atlas trick and rendering 4 vertices per cube face?

This is a picture of what I have currently (in wireframe). 4 vertices per face seems extremely inefficient to me.