Hey EH.  I can create as many templates as I want and they can all say different things  So you should be able to as well.  

What I can not do because the system can't do it, is have different contacts get the different templates.  So if I make a Packing Slip template to go to shipping and the Sales Rep it goes to a fixed list of recipients.  The owner, the AP clerk, shipping dept, etc.  Or I have to remember to add and delete the recipients for each customer depending on who wants to see what.