Just ran a test render using Cyphyr's alpine grayscale map image he posted. I had to tile the image using Photoshop for no seams. Additionally, since its an image and not procedural, the resolution and detail is limited, so I had to rely solely on the alpine fractal's detail settings to break up the image somewhat. It helped, but you can still see the limitations in using images, such as softness and flat color. A procedural method is the way to go for ultimate detail.