You can get a full SRAM Rival groupset from gvhbikes.com for $660. Add on $200 for good wheels, and then factor in headset ($20 at the cheapest), seatpost ($20 at the cheapest), stem ($20 cheapest), bars ($45), tape ($10), tires ($40 total cheapest), pedals ($45) and you're there.

Not too bad, really. Of course, you now need a headset press (homemade easily), BB tool, a set of allen wrenches and an open day!

Oh crap, I forgot the seat. That ones up to you, but anywhere from $30 (E3 Form) to $200.