I've been making dies for my own use and for another coiner for a while... finally decided to try making some sets and selling them. Here's a set put on ebay recently:
http://cgi.ebay.com/Coining-dies-too...mZ130232288014
They are 4" long, made from 3/4" diameter W1 tool steel, hardened and tempered, with a softer shank to avoid shattering. They're designed for making a 3/8" diameter miniature St Gaudens $20 gold piece by hand hammering, but of course that design could be used on almost anything. A trial strike from the dies in .999 gold is included.
By the way, the coining press mentioned a few posts above is still available.