It's possible, newintown. I just remember that the one that friends of mine worked on at the Cleveland Playhouse back in 2006 or so, and that was a co-production with, I think, Actors' Theatre of Louisville, was directed by Amanda Dehnert. I don't know which came first, Griffin's two piano production or Dehnert's, but, from what I recall hearing, Dehnert took the small-scale concept much further than Griffin, giving the show a very Brechtian feel; no set, costume changes happening on stage in view of the audience by adding pieces that were scattered around the stage, that sort of thing.
I'll also add that Susan Schulman also did a stripped down
Sweeney Todd some fifteen years before Doyle did his own small-scale take on the show.
ETA - a quick Google search shows that Amanda Dehnert has been mounting this production at least as early as 2000 (at the Trinity Rep) and it is part of this upcoming season at Oregon Shakespeare Festival. So there must be something to it if so many companies are willing to keep mounting it.
Updated On: 1/18/13 at 02:14 PM