I know of two places right by Marienplatz. They're borderline within sight of one another. Paulaner Im Tal has their own. Berni's Nudelbrett (an Italian place) has one from Thurn & Taxis.
How long have they been offering the Roggen? I ask because I'd hate to think I missed it in the past.
No clue historically, but I first tried it there in 2009. I saw it again (but didn't order it) 3-4 years ago, too. I'm pretty sure Roggen is always available at both spots, although if one was going to disappear it's probably the T&T one. Paulaner owns that brand, so it isn't crazy to think they'd dissolve it in favor of their own.
