Couldn't agree more with the comments above. I would only add sheers; they add lovely filtered light and keep the room looking clean. The full scale of the sheers also adds a sense of luxury. I've included a photo of a master bedroom where there were different size windows and even doors to a verandah. Unfortunately the photo doesn't show the entire wall but hopefully you get the idea. All have block out blinds behind them too. And another bonus; sheers are not as expensive as most other window treatments.

There must be like over a thousand ways to do this. Get 4 lengths of metal tubing. You can get this in chrome and in various shapes and sizes. Put in 4 ceiling hooks, space them based on length of tubing. Feed rope through tubing and tie off. Use a rope colour that is the same as the tubing. Hang your newly created rail / frame using heavy duty fishing wire at points where rope is exposed. Finally Place mosquito net that has a top cover over the frame that is hanging from your ceiling.

Width: cover around 20cm more than your window at each side. Example your window is 200cm, curtains total width will be cover around 240cm. curtains will be around 480cm width in total after gather or with waves. Height: you need add about 20cm above the upper window frame, and fall along the bottom edge of the window frame or 25cm below. Example your window is 150cm height, curtains would be at least 195cm height or fall 2cm above the floor. We suggest you install the hardware first. Generally, curtain rods or tracks are installed about 15cm above the upper window frame. After that, different heading styles may slightly difference height. Add a simple valance will be much lovely with adequate budget. We have many curtains on our website and we provide fabric samples. Please refer to www.curtains4australia.com

another idea if you had a plain pelmet that was within the alcove that came from the bottom of the picture rail to the top of the window and flush with the walls on both sides painted the same as the wall colour., you could then run your black curtain rod across the alcove pelmet which would look like the wall. When I had my Ferderation House we painted the bedroom walls up to and including the picture rail in the same colour. The wall above the picture rail and the ceiling were painted flat white, along with skirting boards, an old painter told me about this and it looks brilliant. A couple more photo's for you with different looks This is similar to what I have tried to explain by running a plain pelmet across the whole alcove and then the black rod running from either side outside the alcove with the curtains against the outer wall, the pelmet would look like part of the wall.