cjc2 wrote:
For this kind of work I would suggest looking into "dye sub" printers. Check out a few brands at B&H. I have one, a Sony which has been discontinued, and it is great for this type of work. The print speed for a 4x6 is usually under 10 seconds, so I' not sure why you would want two. Just to have a backup would, of course, be a good idea, but I would most likely set up another size on that printer. MUCH better than dragging an inkjet all over the place, IMHO. Best of luck!
The Selphy (from above) is a dye sub printer. However, be aware that dye sub prints are quite expensive to make.