Hidden doors/foldaway wall?

[ODFOx]

We're extending and I don't want the space to be open plan most of the time, but definitely sometimes.
I thought of perhaps a wall of bespoke bookcases which pivot out of the way or fold like a chunky bifold? The space to fill is approx 4m long. When closed I'd like it be as soundproof as a normal wall if possible, so that the rooms feel truly separate.
Does anyone have any ideas or recommendations? Thank you

I've been looking at similar options but haven't seen anything that fits yet. Hope some others have good ideas.

If you have a search on "gib doors" you might find some useful info. Gib doors aren't what you're looking for, they're a hidden door in a fixed wall, but the mechanisms (hinges, slides etc.) might point you in the right direction.

I found these hinges. Does anyone else have any experience if this type of design? Thanks

www.fritsjurgens.com/projects/bookcase-door-with-hidden-pivot-hinges

I think your biggest challenge will be getting the sound insulation. A regular door is fairly thin light weight material that works on thin hinges. A wall with proper sound insulation is big & heavy. Getting a big heavy thing to work on hinges is not easy. Something that slides on wheels might work better.

this one is very cool

www.wired.com/2014/11/moving-walls-transform-tiny-apartment-5-room-home/