I am dreaming about a custom some day ..... just because. As i am looking around at sites/builders there is a ton beautiful bikes and approachs out there.
I have in my mind that one element of a really complete builder/designer is that the forks are also custom to each bike, which as best i can tell is not always the case.
beyond that looking to see what builder is doing with with lugs is always of interest.
it also seem that the best builders often have the best painters do the paint.
A pairing like this that comes to mind is Dave Kirk, who sends his frames to Joe Bell for painting (Rivendell uses Joe bell also) but that is not to say that there are not others out there, this is just one who I am looking at closely.
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Life is too short not to ride the best bike you have, as much as you can.