I am imagining something like a vertical blind which you can pull across when needed and that retracts into a fitting on the wall when not. I can;t find one online so don't know if it exists or not (if not then quick, patent it and start production - I'd love one!)
We had a KiddyGuard stairgate for years until DS1 had stopped sleepwalking. It has a sort of alarm on it if the child gets it undone. Very good for wide or unusual shaped stairs. We put ours at the top of the stairs on th elanding and closed it when we went to bed.
We had one, and a friend i visited this week has one (they bought it recently but i don't know the make). I realised what i hated about ours was that you cannot undo it one handed. Soooooooo frustrating.
We have the Kiddyguard one and it's superb. My older children can undo it and go up/down the stairs, but it stops the toddler! You do need two hands, but tbh it's worth it to not have a normal stair gate swinging all over the place!
We have one and we thought it was great. Likewise a Babyden for dividing a room. Alas now our cute baby is now a stroppy preschooler they have to be ebayed so anyone who wants one watch out in the next week or two!
We have exactly what you are describing - 2 of them as our stairs very awkward. Our dc are now 4 and 6 and they are still on the stairs - never quite got round to removing them!! If you live anywhere near Portsmouth - we could come to an arrangement? They're in excellent condition.
Umm, we have the kiddyguard one and love it. You can undo it one handed though - you can release the thumb catch on one side, and then release the gate one the other side without holding the thumb catch down. The only problem with that method is that it makes a loud 'ratcheting' noise as the gate retracts so no good once the kiddies are sleeping.