Great job indeed.
This is what Master Replicas should have given us to begin with.
Version 1 of MR's AT-AT really needed more weathering. It was not a very good paint job considering the price. In fact in my opinion it was the least well done of all other MR vehicle replicas. However the Signiture Edition (version 2) i think is far supperior and I would not have touched that.
Take a look at what v1 should have been. Photos taken from Toy Fair 2004.
http://www.rebelscum.com/mratat.asp