Budget brides - you're not alone! Check out this video from CNN on the trends of budget weddings and today's economy. http://tinyurl.com/6ou7q5
One idea to help save is to have the lower layers of your cake be cardboard or styrofoam covered in fondant. The cake will look like the towering masterpiece you want, but without the giant pricetag. Your guests will have their pieces sliced from a sheet cake - far less expensive!
If that doesn't appeal to you, take a suggestion from Jenna Bush and create the illusion of a taller cake by propping it up on a tall cake stand and filling it in with flowers.