Please consider a few things before you begin this project. First, not every balloon works. They don't always release. If you can find the strong punching-bag type balloon, choose that one. Some people are allergic to latex so be aware that most balloons are made from latex.
Inflate the balloon. Secure it closed with a ribbon (you will need to untie this later). Dip the bottom of the balloon in the tempered dark chocolate. This will create a base. Set the wet chocolate onto a parchment paper-lined surface. Make sure it stands straight. Let the chocolate set until firm.
Place tempered dark chocolate in a cornet. The next step will be easier if you have an assistant. Have the assistant hold the balloon horizontally in front of you while you pipe chocolate lines from top to bottom all the way around the surface. When complete, drizzle more lines diagonally across the existing lines. Apply a bit more chocolate near the top opening and near the bottom to provide extra support. This will form a bird cage effect. Let the chocolate set. When the chocolate begins to harden, release a little bit of the air from the balloon, just enough so the balloon retracts slightly (about 1/8-inch from the outside). Carefully set the chocolate covered balloon aside. Depending on your room temperature, it will take a good 10 minutes to set.
Make the balloon flowers. Inflate 10 small balloons and close them with ribbons. Your presentation will be more interesting if you inflate them to different degrees to make different size flowers. Dip each balloon anywhere from 1 to 3 times to create different number of petals on each. To accomplish that, dip the balloon once, spin it slightly, dip it again, etc. Set each dipped balloon on a parchment paper-lined baking sheet and allow the chocolate to set.
When set, pop the balloon and remove the deflated balloon from the flower. Use cocoa butter paints to decorate the inside of the flowers. Let the paint set. If you made different sizes, you can layer the balloon flowers by setting one inside another. Use tempered chocolate to "glue" them together.
Slowly deflate the large balloon that is inside the large chocolate cage by untying its ribbon. Carefully pull the deflated balloon through the hole at the top. Use tempered chocolate to "glue" the chocolate flowers onto the large cage. Reserve one to cover the hole at the top.