This sample project demonstrates how to export many different reports to one big PDF file and create a PDF file with a lot of report copies. For example, create one rendered report and add it 30 times in the output PDF file. Create the new report object and enable the necessary options:

private void buttonExportClick(object sender, EventArgs e)
{
	var report = new StiReport();
	report.ReportCacheMode = StiReportCacheMode.On;
	report.RenderedPages.CanUseCacheMode = true;
	report.RenderedPages.CacheMode = true;
	report.RenderedPages.Clear();
	report.ReportUnit = StiReportUnitType.HundredthsOfInch;

...

Then, add the rendered report 30 times:

...

	var tempReport = new StiReport();
	for (int index = 0; index < 30; index++)
	{
		using (var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream(
			"ExportManyFilesToOneBigPDF.MasterDetail.mdc"))
		{
			tempReport.LoadDocument(stream);
		}
		tempReport.ReportUnit = report.ReportUnit;
		foreach (StiPage page in tempReport.RenderedPages)
		{
			page.Report = tempReport;
			page.Guid = System.Guid.NewGuid().ToString().Replace("-", "");
			report.RenderedPages.Add(page);
		}
	}

...

In the end, export the report:

...

	report.ExportDocument(StiExportFormat.Pdf, "d:\\1.pdf");
}

In the screenshot below you can see the result of the sample code: