I would like to help you out on this one but really, it is hard when you may not have access to shops that sell lots of fabrics. Having a local store that carries fabrics to browse around makes it so much easier to generate ideas.
Of course you could do alot of internet searching with topics like "music", "home theatre curtains", etc. but it is kind of essential to see a sample of the fabric in your hands.
We looked around at Fabricland, Home Sense, Home Outfitters and Jysk for curtains pre-made plus other fabrics. Ultimately for the main floor we bought pre-made curtains but for the media room the spouse sewed some heavy duty, dark blue velour with some neat fleur de lis clips for the top.
The heavy weight not only blocks out light but acts as a great reflection reducer over the glass french doors.
Kind of like this:
