New 3DRealms Game?

A comment on a story on Game Matters on original games (thanks GameGossip and HomeLAN Fed) has a quote from 3DRealms' Scott Miller that indicates they've got another game in the works other than Duke Nukem Forever. Here's the whole deal for now:
Id is now working on an original project, and although we're known for Duke, we also helped bring Max Payne to the market, and we're currently working on an unannounced original game, too.