I have heard that the Green Bay Rackers have made a steinbier or two. Unfortunately I am not a member there and am not privy to how they did it or how it turned out. I just heard that they've tried it. Might be worth an inquiry if you know anyone there.
To my knowledge, Riverwest Stein Beer by Lakefront Brewing is a steinbier in name only, I don't think they use hot rocks... but I could be wrong.
Guess I'm not much help. One thing I can say is to confirm that based on what I've heard, it is a Vienna/Oktoberfest style beer, just that it uses hot rocks for all the boiling. Again, Riverwest is in name only... they use a buttload of hops, so style-wise it falls someplace between Vienna and APA. Not too far different from a Sam Adams Boston Lager, really. Or an "International Amber Lager" per the drafted 2014 BJCP. Or a "Czech Amber Lager" with German hops instead of Saaz.
I'd love to brew a more traditional version sometime. I understand the concept and have ideas on how to do it, but probably never will do it myself, maybe only if my club wants to give it a shot. Better know your rocks before you try brewing one so they don't explode on you, and lower them in somehow to avoid splashing. Also account for the volume of the rocks in the kettle, i.e., only fill the kettle like 1/3 to 1/2 with wort, to leave room for all them hot rocks. Safety equipment and keeping your distance would be very wise.
Edited by dmtaylor, 15 July 2014 - 12:34 PM.