One workaround: create smart list for count of leads submitting each of the suspected top 5-10 forms.
With lead performance report you can add custom columns based on smart lists. So the report would show a count of leads per form for each column.
Alternatively, you can download list of conversions in last x days and within Excel match each page to the proper form. When you click on a form you can see the list of landing pages using it, so this isn't as daunting as it sounds.