While everyone is still abuzz about the Calatrava Spire (it just won approval for a zoning change, btw), developers have quietly pushed a plan for a 49-story condo tower in downtown Evanston that would become the tallest building ever in Chicago's suburbs. If you've visited Evanston lately, you know that it's gotten pretty tall in recent years, but this one would be twice as tall as what's there now.