I just looked through the current issue of Martha Stewart Weddings, and there's a fantastic decoupage idea in one of the featured weddings. What a wonderful idea for a table setting that can also be a gift for your guests. Decoupage (from the verb decouper, "to cut out") became all the rage in 17th c. France. Marie Antoinette is said to have been a fan of the technique...so let your guests eat cake and keep their plate ;)
Decoupage is a fairly easy, but if you do go with this idea I think that you should make chargers (so that the actual plate goes on top of the charger). In general, a charger is about 11.5 to 13", but they can be larger if you so desire. You can find used charger plates online, or maybe someone in your family has a few they wouldn't mind giving away.
*These lovely decoupage pieces are by Lorena Siminovich of Petit Collage. Each print is available for $140, and would make a nice addition to your wedding registry.
For more ideas and techniques check out:
Handmade by Allison