not directly on point, but I got a 7005 aluminum w/carbon fork Scattante frame from performance last fall, for $159 (counting various discounts). I looked at the Nashbar stuff too, but this was a little better deal. I assume they both go to the same asian builders and use the same raw materials.
I can say the quality, fit and finish and so forth was great. I know enough welding to know that whoever is making those aluminum frames is very very good at it. The finished bike was smooth and stable, a sweet ride right off, and light and stiff enough to be a lot of fun on the climbs. I know I am missing out on what you can get out of carbon, but for the money I had to spend I am pretty happy. It probably would have worked about the same going through nashbar - there's just some well-made cheap frames around now.