Are you guys talking complete uppers, or is the BCG not included? I ask because Sherluk Marketing (google it) sells uppers without the BCG in a variety of configurations for $375. They aren't machined, but they work well. For just over $500 you can get everything except the stripped lower from them. If you're just looking to build an AR at a good price, it's worth checking their site.
Those machined parts certainly appeal to a guys aesthetic sense, don't they? They make a regular cast lower or upper look pretty bad by comparison. Still, most AR shooters are more interested in function than beauty at this point. It is good to see the design taking on a little class, though. I think even anti's would have to admit those machined receivers are a nice piece of work and admire them if only for that.
If this keeps up we'll be seeing ARs with receivers made from steel with a Colt Royal Blue finish and a shiny wood stock.