Do you really need 6 channels on your amp to Zone 2? If you do then you would probably need to get a 7 channel amp since I don't know of many budget ones in 6 channels. You might have an interesting wiring setup if you want to take a 2 channel Zone 2 output from your receiver and send it to 3 pairs of speakers in your house.
Emotiva, as rated by people here and other places, seems to be a great budget-minded amp maker that has 2, 5, and 7 channel options. Go here to check them out: http://www.emotiva.com/
After reading tons on your forums it seems like the most economical way of setting-up multi room audio in my home is by purchasing a receiver for my home theatre and using the pre-out to connect to a multi-channel amp to power the other speakers in the house. Do you agree? And if so can you recommend a budget amp (6 channels) under $1,000?