While I agree with PJ that it is most probably a Viotti creation, I want to point out that in the book 'La Lancia' by Wim Oude Weernink, the car is identified as: ...Turin coachbuilder Motto with his interpretation for an aerodynamic Mille Miglia coupé in 1938, to be driven by Luigi 'Gigi' Villoresi.
But according to 'La Sport e i suoi artigiani' Gigi Villoresi drove a Lancia Aprilia Zagato during the 1938 Mille Miglia.
Is it possible that Motto indeed made the body in white for Viotti as als15 suggests in his post #6?