In the Master Bathroom of the Christmas Showhouse are two HUGE windows. I struggled with what to do with these windows - they are a little awkward: not centered in the space with a window ledge. The size of the window is not right for roman shades (too heavy to open) and the space is a little cramped for full curtains. Ultimately because the view is amazing and no one will be using the toilet during the Showhouse the windows will remain naked until the new owners move in.
When they do (whomever they are) this is what I would do: Delia Shades.
Searching through old Domino's like I do, I came across an old article on Delia Shades. Each shade is designed and scaled to fit the window. They send photos for approval so clients know exactly what their windows (& room) will look like with the shades. You have control over how sheer you want to go. Perfect!