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If that Rossin had a rear cable hanger, then smallfury's point about getting the wheel in might be right. Plus doesn't the low BB sounds like a TT frame?

The only thing I wonder is the drilling. the rear brake bridge looks like it was designed for a brake, but not the front.

Most weird frame designs of roughly that era, are ways of shortening the wheelbase and/or the chainstays.

Its a guess by me. But the odds are good.