Dynamic, partial bedprobing

I have a relatively large print-bed on my 3d-printer so that I need many probing-points to get an accurate bed mesh. Therefore bed-probing takes ages but most times only a small part of the printbed is used printing on.
I had the idea, that the printer could analyse the first layer of the print to get the area of the printbed, that is printed on and then only probe that area before printing.
Is this already a thing? What do you think of this idea?

Why not save your mesh and load it rather than performing a new mesh with every print?

I could also use something like this, mostly because my print area is somewhat weird.

Analizing the first layer does not sound like a ver good idea and I am pretty sure it would not even be possible because klipper would not even have that information when it needs to probe (at least if it prints from streamed gcode). So that part would probably fit better either into the slicer or an octoprint plugin that analizes the area of the whole print.

Klipper allready allows to specify the probing parameters in the probe command.

A little macro and slicer setting/post processing can help.