Yes, I have also noticed that Access 2007 mails only one report at a time.
I generally export the reports to .pdf files & then send the reports via Outlook mail, as attachments. Just right click on the report & then select Export as .pdf.
Note: It does require proper .pdf executables to be installed. If not, the system will guide on installing pdf. I realize this is not best solution but this is the way I am circumventing Access 2007 shortcomings.