This is an excellent idea! So if you had a table of 10 people, you could serve a miniature cake that would feed 10+ (so everyone could have an extra piece right?). The only disadvantage to this idea is that you would have to purchase a serving set or at least get the venue to provide it, and have the guests cut their own cake. It might be kind of awkward if the waitstaff came around to each table to cut the guest's cake.
