There aren't that many sold because they have to compete with "real" 9mm pistols, that generally have a lot more features and functionality for the same or lower price - everything from polymer, alloy, or steel frames to reliable high capacity mags, DA/SA and DA/SA/Decocker and hammerless actions, in a wide range of sizes and styles from very compact to big and heavy.
That said, a friend of mine has an 80's Colt in 9mm. It shoots just like a .45 except with a little less recoil.