Wow! What an incredible view to have! Can you just install floor to ceiling curtains?

they are at an angle, er... so you couldnt open them without one side dragging or the other having flood length.

Are you looking for a window treatment for privacy, aesthetics, reduce sun glare, etc.? The best window treatment really depends on what you are trying to accomplish.

Have you looked into custom shades at all? If you can find someone to make the custom shape, some sheer fabric shades would keep the heat and glare out without completely losing the natural light. If you also want darker shades (if small ones will be napping in here) you can get shades that have sheers underneath heavier fabric for some roman shades style window treatments.