As many widgets showing as the site height allows

Hi,

I have different widgets in my right sidebar (twenty twelve child theme) and I was wondering if there’s a plugin where the number of widgets displayed will depend on the height of the page?

Example:
I have very long posts on a specific page, the sidebar shows over a dozen of widgets.
On another page, the text is only very limited. Therefore, it shows only a few widgets.

At the moment it’s the widgets that are ‘stretching’ the page. They are the ones that (also) define the height of the page.

In case there’s no such thing – do you think it would be hard to make?

Thanks ??