DDP out of the box can not do this. You can create the index page by exporting a separate MXD to PDF. Then use arcpy.mapping (Python scripting) to append the pages into a single result.Here is a snippet from the arcpy.mapping PDFDocument class help:
import arcpy, os
#Set file name and remove if it already exists
pdfPath = r"C:\Project\ParcelAtlasMapBook.pdf"
if os.path.exists(pdfPath):
os.remove(pdfPath)
#Create the file and append pages
pdfDoc = arcpy.mapping.PDFDocumentCreate(pdfPath)
pdfDoc.appendPages(r"C:\Project\Title.pdf")
pdfDoc.appendPages(r"C:\Project\ParcelAtlas.pdf")
#Commit changes and delete variable reference
pdfDoc.saveAndClose()
del pdfDoc
Jeff