so what is the correct way to tell my data object how it should present itself?

Of course there is never the correct way :-)

However, it might help to split the functionality into three layers:

1. Reports - to handle the details of the different report types (RevenueReport, SalesReport, etc.)
2. ReportFormatters - take report objects and provide a format-independent API to their structure (e.g. $rf->header, $rf->content, etc.)
3. ReportRenderers - that take a ReportFormat object and output it in a particular format (ReportRenderPDF, ReportRenderHTML, etc.)

So all the report specific information stays in the Report class. All the output-format specific information stays in the ReportRender classes.

Hopefully this makes some sort of vague sense :-)

Update: Just noticed - this was my 1000th post. Gosh.