Curtains would be good too. Blocko curtains of course though.
For Curtains and Net Curtains, I like to place one of the 3-Brick High ramps in front of the window. I then paint it a Trans-White, if it's a Net Curtain.
For Blinds, couldn't you do some 1x1x4 plates (Depending on size of window) and then stack them up, and make every odd one invisible, via Rendering?
You could even do a Named bricks event and have the bottom one, once clicked, turn all the bricks Non-Rendering, Collision and Raycasting.
That's just an alternative idea. It'd probably be easier to make it via bricks, than to wait for someone to make some Content_Blinds.
They're not 100% the top priority for things to be made out of Content.