Leaded glass windows, stained glass, staff meeting room, antique panels?it all sounds a little like a Gothic cathedral. But it's actually the fifth and sixth-floor duplex at posh 998 Fifth Avenue, currently owned by a member of the Milstein dynasty. She picked it up for $15.75 million in 2006 and renovated it, and now it's time to try for a little profit. But there's the slightly unfortunate matter of the floorplan, which has no park views from any of the main rooms' windows. Which means the apartment is now asking the low, low price of, uh, $23 million.