You can import a scan into V-Carve Pro, and then you can convert it to vectors and create toolpaths, but I think you'd need to scale it to the correct size, as I don't think the image contains any size info. Some formats do, but I don't think that V Carve would use that info. Also, the raster to vector conversion may change the sizes slightly.
Imo, drawing a .dxf involves fewer steps than you're talking about. You need to lay out your design, cut it, scan it, convert to vectors, then create toolpaths. For me, I'd draw it, and then create toolpaths. Most likely I could have it drawn before you can have it cut. Unless, you're talking about complex freeform shapes. But even then, how are you laying out the esign to be cut? Ther must be some drawing involved? Or are they just cut freehand?
There is another option. MeshCAM can load an image and create a 3D part. The image should preferably be 2 colors (white background). In MeshCAM, you can use the pencil toolpath option to try to just cut the perimeter of the part. This may work, but I would NOT recommend it, as it's not what the software was designed for.