Are these transparencies that you buy and print on? If so I know officeworks offer the same but you provide the artwork and then they print it on A4 for less than a couple of bucks. So if that helps, you will also be able to get them to print colour graphics as well
good point as you could do a say red box with the font in front of it to simulate your desired coin plate and officeworks run transparencies through their photo developer which gives a stronger, truer colour and sharper image. I recently did this for something pin related that I am working on with excellent results.
