Seems to me the simple way to hack this camera for 3x4 would be to get a $5 pack-film Polaroid (the ones that used the 100 series film, now reissued as 600 series Professional pack film -- plastic lens and no rangefinder would be the preferred, since the better ones are decent cameras as is), cut it just forward of the film pack recess, and graft it to the back of the 110A, cut at the film plane. Done carefully, this would require a minimum amount of focus reset, and allow use of modern Polaroid materials with the good rangefinder, excellent lens and manual exposure capability of the 110A. You get access to pos/neg, high speed B&W, and middle speed B&W and color emulsions, possibly including Fuji films (I don't recall if Fuji makes a 600 series compatible pack film to match their well-reputed 4x5 single-exposure offerings).

The camera would be much more versatile, however, with a 4x5 spring or Graflok back, allowing use of Polaroid single and pack films in the appropriate holders as well as regular sheet film in standard holders. If you have a Graflok handy, the conversion should be relatively simple (compared to, say, building a Space Shuttle with only a hammer, straight-blade screwdriver, and yardstick).