What was the depth of field there, about a meter? Would an extra 60cm have made much difference? I doubt it. Or if it really did then you could've have used the money saved by getting a crop body to get a 35mm f/1.8 (assuming you used the 50mm, if it was the 85mm then just use the 50mm on crop) and get the same depth of field and a better lens.
The EXIF indicates a shooting distance of 2 meters, so the DOF (according to http://www.dofmaster.com/dofjs.html) would have been .17 meter. To equal that with a 1.6X crop and achieve the same framing from the same shooting distance (for the same perspective) would require a focal length of 31.25mm shooting at about f/1.2 (I got this using the closest focal length in the calculator, 31.4mm). More realistically, using a Sigma 30mm f/1.4, which would come very close to duplicating the framing from the same shooting distance of 2 meters, the DOF would be .24 meter or 7cm more than the full frame (about 3 inches for us non-metric types). To duplicate the .17 meter DOF with the crop at 50mm and f/1.8 the crop would have to be shot from a shooting distance of 2.5 meters, which would change the perspective and framing. Most fun of all, if the subject were small enough in the frame so that it would fit in the crop frame using the 50mm focal length at the original 2 meters shooting distance, at f/1.8 the crop would have .11 meter DOF, .06 meter less than the full frame. Bottom line: as with many other things, this is all relative.