Hi,
I know you say jewelry isn't an option, but what about a heart on it, a locket......put a pic of you in it, put her graduation date on it or a nice saying like you love her. That is something she can keep, wear, think of you and hand done to her daughter someday. Which makes it very special........I have a bracelet my Mom bought me years ago, nothing special, and at the time, being a tomboy, I didn't even wear jewelry, but after my Mom died, that became something very near and dear to me.......
Think about it......everything else, will be a picture or a memory, but something engraved and a keepsake is special.
Good luck with the decision and I hope you have a great graduation! And congrats on a great daughter.