Instead of numbering your tables, why don't you name them after characters? You can have a Cinderella table for bride's parents, a Prince Charming table for groom's parents, a Jacques table, a Fairy Godmother, etc., I'm sure that you can find clipart or pictures of the characters at various websites. You can buy small tent cards at places like Staples, etc. and print them yourself. You can print larger cards for the tables with the pictures on them to denote which table is which.
My DH's uncle did this for his wedding only he used pictures from and names of Italian cities.