Can SimpleQB be used to scan in receipts and invoices which are then matched to the files kept in the QuickBooks System?

Please refer to the Wiki Documentation for the complete SimpleQB reference.

Yes, That is exactly what SimpleQB was designed to do.

SimpleQB uses the information from your QuickBooks documents to file images under the appropriate customer/vendor, document type, document number and date. Simply pull up the corresponding file in QuickBooks and click scan!