How do you set the visible area of a grid to a logical number of rows?

From what I can see, it appears you can only set the size of the visible scrollable area of a grid via a CSS to a fixed percentage of the screen (or if you use an iframe to achive the same thing).

Is it possible to set the visible area of a grid relative to a number of rows?

For example, if I have 100 rows but I only want 10 to be visible in the display. Is this possible?