Rear derailleur arrived, not new, but not hideous.
The Dura Ace headset in black is pretty scarce, but I found a new Suntour XC Pro in black which will fit. Once I have the headset, I'll start putting together the bike. I'm selecting lighter weight components for this bike than I did for my last project (Nishiki Pro Tour), it won't make too much of a difference, but hunting for the parts is half the fun.