Thats good to hear about having good guides in Cambodia. Be careful if you go, it seems just about anyone could claim to be a "guide" there, and some of them just suck, but on a different point of view, I guess they need money, but sometimes they are so pestering! Argh Even little kids. (Don't take this comment offensive as I am Cambodian too, and only speak from experience)

And if anyone has a semi large group, up to 15 people and need a driver, I have a really great recommendation, he is based in Phnom Pehn, but he can take you all through out Cambodia, and we just heard he got a new van to drive. =D