Each student writes a small note to the others in the class describing how eachof their fellow classmates contributed to their sucess.  these can be put in an envelope for each student as a rememberance.

We are a large school so we have a very large graduation ceremony. However, the night before we also do a "pinning" ceremony. We purchase the students sterling silver lapel pins (see link below) and have them approach the stage with a sponser. Their sponser is typically a loved one who  has supported them through their education. As a group we say a brief oath or statement of professionalism and then have their sponsers pin them. It's very moving and allows the families to be a part of the celebration.

Maybe you could implement something along these lines. Congratulations and good luck!

http://www.foothillsdiamonds.com/cemathc.html