Create Segments in ReportBuilder Based on Dynamic Values

In ReportBuilder, I think it would be useful to create segments that change dynamically based on the output of data requests.  Currently, ReportBuilder allows you to apply segments to data requests, but they have to be pre-created in the SiteCatalyst 15 interface.  I think it could be incredibly useful to be able to allow segments to be based on a given period's top reported report line-item.