This cake below is so adorable, a personal fave, and what intially got me started on this whole button idea. Can't you image a plethora of matching invites, save the dates, and bouquets to melt your heart?
images (in almost order) via jessicaclair.net, hellocrafty, marthastewart.com, the knot, prettychicky.com, loveandlavendar.com and brides.com