If you really want to do it right, use a reproduction stand similar to an enlarger. The key is to insure the camera's sensor and the cards are exactly parallel to one another, otherwise any angle between the two will distort the shapes of the lettering.

If you're too concerned about the shadows cast by the embossing to use a flatbed scanner, you'll need several diffuse light sources from around the sides of your platform. For consistency's sake, use stable light sources that don't flicker or vary their color output.

For continuous lighting, good old incandescent bulbs combined with umbrella reflectors or shoot through umbrellas are ideal for this. Just be sure to use the same type of bulb in each light. More modern CFL and LED bulbs can have issues with flicker and limited spectrum output that can make accurate color reproduction impossible.

For strobes/flashes you also need to insure that all of your lights can output the same amount and color/spectrum of light. In addition to the modifiers suggested for continuous lighting, flashes are usually bright enough that you can also reflect them off neutral colored walls and ceilings if the room is the right size and shape.

Ideally you would set this up in an area with no natural light that can vary from one moment to the next depending on the weather, time of day, etc.

Large commercial reproduction houses use large format style cameras with digital scan backs to do very high resolution reproduction work. Short of that, use the highest resolution camera you can combined with the flattest field lens you can get your hands on. Most macro lenses have very flat fields of focus. So do many (but certainly not all) normal prime lenses.

For example, the Canon EF 85mm f/1.2 L II is a very expensive lens that is prized for the "look" it gives certain styles of portraits. That look is a result of the lens' field curvature. Even though it is a $2,000 lens, it would be totally inappropriate for serious reproduction work. The $350 EF 85mm f/1.8 would be far more appropriate as it has a flatter field of focus. The EF 100mm f/2.8 Macro would be even better, as it is optimized to perform at very close distances with a very flat field of focus.

A normal lens is one with a focal length roughly equal to the diagonal of the image format/sensor size.