Finally, an update and in fact the final version!
Pretty much everything except the base terrains have changed since the first version.
For anyone interested here is the list of vegetation used and where it appears:
Foreground grasses - 3 varieties by Walli
Midground grass - 1 variety by Klas
Midground bushes - 3 varieties by Walli
Tree coverage for the hills - 1 variety of Oak and 1 variety of Silver Birch by Klas
Tree coverage for the background hills leading up to the mountains - 2 varieties of Pine by Walli
Rendered at:
Detail: 1
AA: 10
GI 2/4
Approximately 13 hours rendering at 1600 x 1000.
Thanks to everyone for their suggestions, they certainly helped!
The image turned out a little larger than I can post here without reducing the quality too much so you can find the full version here, just click on the image to get full size:
http://www.archer-designs.com/zp/index.php?album=digital-art%2Fterragen-2&image=mission-peak-preserve-v7.jpg