AMT is out of business (I own an Automag III), and Taurus quit making the "Raging Thirty". I believe Ruger still makes the .30 Blackhawk, which I also own. Olympic Arms has an upper in .30 carbine in their catalog, although I have never seen one.
You get lots of attention at the range - lots of noise and flame from the .30 carbine handguns.
Lee