So, I've done the custom grail bike thing, and it was both fun and frustrating. In the end, though, I wound up with a beautifully built, comfortable bike that can be set up several different ways.
This is the 'standard' early 80's Campagnolo Super Record build:



This is the Cino Heroica/L'Eroica setup, with 32mm Gravel Kings, compact crankset, Deore derailleurs, and a 13-34 freewheel:



And this is a 650B setup I toyed with in the Fall, with 38mm Loup Loup Pass tires: