There is an easy way to achieve this without adding a new element, and the circuit isn't even that large...
Just put input to be PSCN touching LCRY, and use it also to power DLAY which powers NSCN turning off LCRY.
you're right, but wouldn't it be more convienient to just have it as one pixel?
Many elements have been rejected, if the only reason has been the potential convenience over the more compact implementation.
I know...
I think I will just stick to what you said, LC (LiquidCaesium)