Here is one of my builds, the seat is a bucket seat frame with one piece leather I cut and lashed, if you look you can see my airhorn on the other side of the bike.
A similar production model starts at 1,200$
Only the front fork and rear triangle are pre-made.
Nice ride Getter! We have a few of those in the area around here where I live and I believe that they must be a factory model or someone making a similar custom as they all look the same and are interesting but since I normally see them as I am headed the opposite direction, have not had a chance to see if there is a make/brand on any of them. I am fairly sure at least one is a professor at the local university. He rides it all over the city. No air horn though.