whitney expansion?

Apparently the Whitney Museum of Contemporary Art is looking to add on, but some problems have been raised. New York is a city where if a business out grows it's space it makes for an interesting dilemma. How will expansion happen in a city where the only way to expand is to buy out the building beside you or add on sky high?

"The Whitney Museum of American Art, heading into a Landmarks Preservation Commission hearing today, will be armed with an alternative design for its proposed addition by Renzo Piano that would not involve the controversial demolition of a brownstone, museum officials confirmed yesterday.
One of those brownstones, 941 Madison Avenue, is considered a "contributing" building - one that is deemed to have artistic, cultural or historic value in a designated historic district. The other, 943 Madison, is not. If the commission were to approval the Whitney plan, it would be the first time that the commission had allowed the demolition of a contributing brownstone in a historic district." NYtimes