Thanks to those who voted in the poll. The answer so far is approximately $200K. This is for an accurate reproduction using mostly new parts. The two major exceptions are gearbox (original late model 6C) and engine (1960 AR 2600). If we used a blown 6C add $100K, 8C add $200K.
To buy a reproduction "off the shelf" would be around $450-650K depending on the spec. So grubbing about for 4 years saved around $300K and made some friends along the way. I'll settle for that.