A new version of the photorealistic scenery alpi has been released, it is no longer free, but costs 18 dollars. It is version 3 of "Alpi".
The author has used a completely new set of picture material, which makes
the scenery look really stunning.
You may want to check the many screenshots here:
http://www.postfrontal.com/Alpi3/ENG/index.php
the set comes in 6 packages à 300 MB (=1.8 GB in total).