Well I wouldn't do 6850's in X-fire, I'd consider just getting a single GPU for now and upgrading later.
* A 6950 2 gb or better would be what I'd consider. With a single GPU solution you would only need about a 400-500w PSU to power the system easily. This would save some $ and could be used for other parts or for some savings.
* The Phenom II x6 isn't always the best solution if it's a gaming system, but it depends on what your doing with the system. I'd say at least a Phenom II x4 955 BE would the least CPU for an AMD system that I'd consider. With a $1k budget I'd seriously consider getting an Intel 2500k CPU or something like that. It all depends on what you want to do. AMD mobo's tend to have more options for less $, so that can be a consideration.
* Is this a new build or are you piecemealing one together??
Well since you mentioned that you have a build on newegg that you haven't made public yet, continue to keep an eye on it and update it with the best parts as things change. It would really help if you made it public, especially when you get close to making a buy so that we can see it and make suggestions.