Is it possible to do Environment Map based lighting in Unity, as described in GPU Gems?
Chapter 10. Real-Time Computation of Dynamic Irradiance Environment Maps
Seeing how open Unity is, I’m sure it’s possible. Would love to hear from anyone with technical know-how! 
Nose
2
I am also interested in this question
Nose
3
Chapter 10. Real-Time Computation of Dynamic Irradiance Environment Maps
Demo and sources
and attempt to convert one of shaders to unity
http://forum.unity3d.com/threads/172689-Image-based-lighting