I take the cheap way out. I use IPSC targets left over from the monthly matches at my home club, Harvard. To simulate steel plates on indoor ranges, I use a stencil of the appropriate diameter and paint with white spray paint. For black bulls, I use the same method with black paint. I use cardboard for these painted targets which works pretty well as far as uniform holes are concerned and has the added advantage of not needing any backing.
For those without steel plates, paper plates of the appropriate size work very well and can be easily mounted on stakes driven into the ground and patched with masking tape.