This immense duplex penthouse with approx. 7,500 square feet of living space (approx. 5,000 interior and approx. 2,500 exterior) has just undergone an award-winning, meticulous, gut-renovation that blends old-world elegance and scale with the comforts of luxurious contemporary living.    Occupying the top 2 floors of this 94'x40' prewar condominium building, this triple mint "townhouse in the sky" with monumental terrace was carefully designed and the result is a thoughtful layout that is perfect for grand entertaining, exhibiting fine art, and serene living.    Some highlights of this exceptional home include: a key-locked elevator that opens into the homes dramatic double-height sky-lit formal entry hall; two master suites; expansive living room with gas fireplace; large professional chefs kitchen with Viking appliances; formal dining room that comfortably seats 14 guests; large terrace with direct access from the second floor living area, complete with second full kitchen and dinette; separate wine and laundry room; gallery-sized walls; skylights throughout; office/library; formal tea room; high ceilings; ample storage; and highest-end finishes throughout including custom American Walnut millwork, museum-quality designer lighting, and SA Baxter architectural hardware.    291 Seventh Avenue is a private boutique building with just 9 full-floor apartments and two elevators. The building is ideally located where Chelsea, Flatiron, NoMad, and the exciting new Hudson Yards converge -- Avenues School, Wholefoods, Eataly, the High Line and Madison Square Park are all within minutes of your front door.