Chombi1 

It is an interesting frame. Certsinly of pretty good quality but it does not seem to reach the level of an artesinal, custom, limited production frame.
There seems to he some attempt of working the points on the lugs to be thin and delicate at the main frame tubes, but the treatment if the seat stay tops and the stay points at the rear dropout, could be done better, as they look quite blunt and abrupt.
A custom builder in the caliber of someone like Bill Davidson or Bill Holland, would have finessed/refined those details on the frame, much more than what we see on this bike. These, plus the very commercial looking applied serial number seems to point to this being more of a mass produced frame from a moderate to big size manufacturer, albeit, maybe a top model in their line.
JMOs......