Up until recently, this palazzo housed Venice's post office. When I was there in November, the post office had moved and the place was closed, but I heard that it had been purchased by Benetton.
A recent NY Times article called "Venice Reclaimed" reveals the plans:
"The Fondaco dei Tedeschi, a giant 13th-century palazzo on the Grand Canal near the Rialto Bridge, caught the eye of the Benetton Group, whose owners have a long history in the Veneto. The company has commissioned Rem Koolhaas’s OMA to create a department store and cultural hub with boutiques, a rooftop terrace overlooking the Grand Canal, and rotating film, architecture and design exhibitions, along with musical performances."
Hmmm. The rooftop terrace might be cool. Every time I pass this palazzo, I think about the fact that it used to be completely covered with frescoes by Giorgione and Titian. They were mostly destroyed by the elements, but there are some fragments in the Galleria Franchetti (the museum in Ca' d'Oro).