This question came out of my '13 MORE Classic Underused Features in GP' at GPUG Summit today. I wasn't sure of the answer so I tested it this evening and sure enough, ISV product tables can be added to the Business Alerts available tables.
Select the Dictionary, Series and the tables you want to add to Business Alerts, insert them in the Selected Tables window and click Process. These tables will now be available for use in the Business Alerts Wizard.
Thanks to my 13 MORE audience for the great questions today!