How many artists are left that are still building truly 100% unique and custom frames and bikes for clients, i.e. a client (presumably with deep pockets) can commission him to build every aspect of the bike, custom frame, custom components, custom paint, all by hand? Like the Chip Foose for bikes.
Pegoretti is the first to jump to mind, but I presume he's been out of the 100% custom business for a while now. Vanilla's turned into a bit of a factory as well. How about Cherubim by Shin-Ichi Konno? Kusaka-san at Kinfolk? Anyone else that's truly an artistic master?