Looking to create a report that shows only the Top 5

I'm trying to create a dashboard report that shows the top 5 people that are overscheduled for the coming week.  I've added a custom field that I would like to put a ranking count in and then have the dashboard report only select those people that have a rank-count <=5.  I haven't been able to find a way to update the count field.  Any suggestions?

I'm told there is a future Clarizen Enhancement for reports to have the top x, but that doesn't help me today.