hi BL,
you can still use a cross-tab for this but you need to encorporate a bunch of formulas to make this work.
have a look at the attached report. extract the contents and change the .txt extension to .rpt.
go to the Design tab of the report. notes:
1) there are two groups on the report
2) the first group is on the same field that will be used as the Cross-tab Row
3) the second group is on the same field that will be used as the Cross-tab Column
4) the third group is on the month of a datefield...this group is only used to create the formulas
5) there are 3 formulas used in the Group sections to create a string running total which is used in the cross-tab
6) go back to Preview the report and right click on the Cross-tab summary and choose Format Field
7) on the Common tab go to the Display String formula...this is the formula that parses out the string running total created in the suppressed group sections above the cross-tab
-jamie