At least they’re consistent. The on-again-off-again penthouse listing at The Mark continues to insist on a $60 million asking, nearly seven years after it first popped up on the market. This is particularly audacious considering the building’s already shaky history, which is fraught with buyer back-outs, lawsuits, and heavy price cuts. Still, the penthouse surges ahead asking more than $6,000 per square foot and daring anyone to challenge it. And what do you get for $60 million dollars plus $44,645 per month in common charges?