Here's what been done at parishes in which I have served. The high school graduates come forward, along with the parents (or grandparents, or whoever the student chooses who has been a significant person in their growing up). There is a litany of blessing, in which the parents place their hands on the head of their child and bless this child who is graduating and going into the world (whether college, or job, or military, or not-too-sure-yet). And then the child/young adult stands and turns to face the parents, and placing a hand on them in blessing (usually on the shoulder, since they feel "funny" about the head thing), give a blessing to them, asking the Lord to watch over the ones who spent so many years watching over them. Sentimental? Yes, there usually isn't a dry eye in the place. But also a lived parable of one's blessings returning to one after many years. (Usually the child also hands the parents a carnation.)
I will also say that this ceremony is the culmination of years of such ceremonies, usually (not always) beginning with the baptism of that child in infancy. It's called "Milestone Ministry" and there's some good material for getting this started in a congregation through the Youth and Family Institute. It could become just a gimmick, but isn't intended to be. At each Milestone the child receives something tangible that is a sign of the milestone being recognized. At this last one, it is the child who gives the gift, rather than receiving one. It is part of an attempt to put parents back in the place of being the primary instructors in the faith to the children in their care, and the congregation being assistants to the families in this role.
(And I actually like the quilt idea, and would probably introduce it if this congregation didn't have at least 20 high school graduates every year.)
