Master detail charts - how can I make it faster?

[JGirl]

I have a report page containing a list with 100 lines.  For each line in the list I'm rendering a chart as another column in the list (the chart comes from a different query, linked to the master (list) by a master detail relationship where the master list has a data item that is linked to a parameter in the detail (chart) query).

So my end report has 100 charts and is always run as PDF.  My chart queries are as lean as they can be (so filtered appropriately, no excess data items), and they are almost instant to return data through the tabular viewer.  The problem is that I can't get the report run time to be under 10 minutes.  If I choose not to render the charts in the output, the report runs in < 2 minutes.

I absolutely have to work with what I've got (as a report author only), so I'm not interested in workarounds (such as upgrading to C10, scheduling the report overnight, applying service packs, remodelling data sources, removing charts from output etc).

Anyone got any tips or tricks on how to make my chart rich report run faster?