have a
custom bike that has some really crazy tube lenths but fits perfect for me.
N+1 on another custom .. have the builder make the rear triangle and tube spec.
suitable for carrying panniers..
Bruce Gordon in Petaluma California is the Go to Guy in the US..
His racks are top of the heap, mine are over 20 years old.. veteran of many tours
His BLT is a Taiwan subcontract ,to compete with all the brands you mention that are also
made over there.. But he is first a very well regarded.. hand builder..