Buy Windows 7 through Microsoft’s online store
Yep, it seems Microsoft launched their own store and didn’t even promote it properly.
They are going to sell Windows 7 there and will probably also offer an instant download through their own store.
Actually, it would make sense that Microsoft sells products online, because who does really need those fancy software boxes nowadays? 
Visit their shop:
Considering that they can make a lot more money by selling online, they also plan to reduce the price of Windows 7 by 10-20%!