Wow I too have the same glass above my doors. Mine are all internal swing doors therefore I don't have your delema. I'm in the middle of renovations and mine are staying. My walls will be dark and modern with all the trim white with the original character and it looks great. With your wall, it's a lot to deal with therefore would suggest replacing the slider with a glass door with timber trim, keep your walls light modern and bright and paint your trim dark (any colour you favour) here is my example to give you an idea of what I'm talking about hopefully you can see the value here is a snippet of my renovation good luck....hope my idea gives you plenty of ideas

You can use a shutter blind, it's pretty good, secure and also allows airflow You can design them @ qualityblinds.com.au and see for yourself which fits better!

FormFunctionNT I love your lego door! So innovative. This idea may be a little busy for the other door, but just putting it out there... You fill it with squares of the 4 colours, but randomly leave 4 blank. Almost like 4 have left and moved 'next door' if you'll pardon the pun! Sorry, I couldn't help myself.

Oklouise and Sirius, thanks for the ideas. Actually the first one could work us very well, removing part of the wall and having a partition instead of a door. A lot more work but we are pretty handy. Regarding the barn door, most of the people I talked to agreed it might date quickly, unless I use a different mechanism than the ubiquitous black one you see everywhere,maybe.