an after meal staple for us is variyali, which is used as a digestive and breath freshener. for weddings, they're typically put in little plastic ziplocs and left on each table (or handed out after dinner).
this personalized sugar packet idea would be awesome for the variyali packs! rather than printing on the glassine envelopes themselves, you could print out labels and use them to close the packages. having to do over 500 of these, the labels would probably be the most economical and less time consuming choice.