Within each report you can right click on the table, choose properties, and modify the number of rows to display. However is there a way to GLOBALLY modify the default maximum amount?
The answer is yes with the required modification occuring within the web deployment area.
WebReportStudioProperties.xml (version 9.2) has a section starting with:
<!-- The following section defines the DEFAULT number of visible table -->
Simply modify the values set as default within the xml tags 'previewDataMaxRows' and 'viewReportMaxRows'.
You will need to restart the web application server (jBoss or Tomcat) for this change to take effect.
There is a SAS Usage Note on this with a 9.1.3 example:
http://support.sas.com/kb/12/961.html