jQuery Grid Plugin - jqGrid

Hi jqgrid people!

I have the following problem, I want to give the user the possibility to choose the number of rows actually visible for him. For example, I always retrive 100 rows from the database (i.e. rowNum option is set to 100). Ok, suppose I just only want to show 20 of them. To accomplish that I am calculating manually the height of the table considering 23px height per row, but this is a dirty patch I think. Isn't there any option to determine only how many rows to show? I know, if I retrieve just 20 rows and set height: 'auto' this will be a solution, but I still want to retrieve more rows and I want the scroll to be present. 100 will be the rows retrieved, 20 just visible in the screen and there will be 80 rows """visible""" with scrolling. Any consideration?

Thanks a lot!