Great render Stefano. Man, how I love Camels (they give me the steady nerves nessicary to work with Bryce 6 hours at a time).

Render times can be a bummer so I usually render each object separtley then assemble them in PhotoShop afterwards adjusting them (color balance, hue/saturation, brightness/contrast) by the object to achieve the final product.

I have some color control issues.