Vent Noirs have brought good prices on eBay though $600 might be a bit high, though maybe not for NOS. I've seen them with early Dura Ace and the black components go well with the black chrome finish on the frame.
B/c of their unique "scratch-proof" finishing VNs draw alot of interest. I like thm alot but am in no position to buy anything right now. Post some pics.