No, you can't eat them. No, they do not contain anything edible. Why then?, you ask...let me explain
I had a dream that cupcakes were hanging from my ceiling (I know, I have very strange dreams) and decided I wanted to make it come true. The problem was...real cupcakes wouldn't last long and would be very gross and heavy. So I decided to make lightweight, fake ones.
Looking on the Internet for instructions was a pain in the butt because everyone had their "secret recipe" they weren't willing to share.
After a long and diligent search, I finally gleaned enough info to start...
so I am going to share all the instructions FOR FREE and to anyone who wants to see them!
You may republish this, you may sell fake cupcakes to your hearts desire, but I do not suggest eating them...
And what else can they be used for? They make great card holders! Just put a card with something along the lines of "Happy Birthday to one SWEET girl" or something cheesy like that. They make wonderful ornaments too, since they are incredibly lightweight. They can hold photos or business cards too...if you own a bakery or know someone who does, they can also be used in window displays. These do NOT contain any food ingredients, so they wont attract pests or animals, mold, rot, or deteriorate. They will last virtually forever.
Now isn't it refreshing to see artistic directions with no strings attached? I'd love too see your pics and hear your ideas too!

Step 1: Supplies

You will need:

a small can of expansion foam (ask for it at your hardware store)
cupcake papers
newspaper
rubber gloves (you WILL want these!)
old clothes (I doubt they will look the same at the end if you're anything like me...)
muffin tin
mini muffin tin and papers (optional)
plastic bags
acrylic paint
sculpey or other polymer clay (optional)
fine glitter (optional)
a container of LIGHTWEIGHT spackle (a little goes a long ways..)
an electric mixer
a spoon
a bowl
pastry bag with star tip (big star tip!)
water-based varnish (optional)
paintbrushes
wire (at least 22 gauge...20 would be about perfect)

Now that you've gone to the hardware store...you're ready to start!

Step 2: Making the "cake"

First, put your muffin tin inside a plastic bag (protection) and place it on the newspaper. Make sure all of your loose clothes and/or hair are tied up and you are wearing old clothes. Put on your lovely plastic gloves (you WILL want these! expansion foam is incredibly sticky...like what would happen if you mixed marshmallow cream with gorilla glue and stuck it in a spray bottle! and water cures it so it doesn't wash off too well....)
Next, push a cupcake paper into each of the wells of the muffin tin. You may want to weigh these down with metal washers...I didn't but it might have been a good idea.
Now you're ready to start spraying!
Open your can of expansion foam....and be warned: one can goes a LONG ways so have plenty of cupcake papers ready! It is also one-time use so be sure you have enough time.
Now, spray the foam into one cup at a time, filling it about halfway full. It will rise just like it does in the oven. The only way to do this right is trial and error...so make plans for a few funky-looking cupcakes. Be really careful if you are doing miniature cupcakes...they overflow fast!
Let each cupcake sit in its well for a few minutes, then you can take them out carefully and set them on your newspaper to finish curing while you make more cupcakes in your tin. When you are done, let the cupcakes cure and throw away your gloves (which will probably be really sticky and gooey by now)

Step 3: Painting the Cake

When your "cakes" are completely dry, you can now paint them to look more like actual cakes. First, break off any huge globs of expansion foam that protrude from the nice dome you should have. Then,
using acrylic paints, put a base layer of the color you want on all visible parts of the dry expansion foam. It is OK if you don't paint the very top; it will be covered with frosting anyways, so pay special attention to the area around the edge. I used a light tan for white cake and a dark brown for chocolate (duh!) but you can make many other flavors such as pumpkin and spice by the use of your paint colors. After your base coat is dry, use a dry-brush technique to put spots of a darker or lighter color over it to make it look more like cake (see picture) You may also be able to use a sponge for this step. Use a small brush to paint the expansion foam's edges inside the paper.

Step 4: Toppings!

Now prepare your toppings! Decide on what you would like on top of your cupcakes and figure out a non-food substitution for them. I made most of mine out of polymer clay which I then baked at 275 degrees F for 15-20 min. I added some acrylic paint to some and used water-based varnish on the ones that were supposed to be shiny. *do not use oil-based products on polymer clay!* they never dry and remain sticky. For the "sugar" I used fine craft glitter. Coconut could easily be made from painted wood curls....just use your creativity to come up with exciting toppings! If you have a great idea, please post it on the comments so that the rest of the art community can use it too!
Once you are done making your yummy toppings, it's time to make the card-holder or ornament-hanger.
Using your wire, make a spiral about the size of a quarter, leaving a tail about 1 1/2" long (see picture) for a card holder
For an ornament hanger, form a "u" shape with ends about 1" long.
That's all there is too it!
To see some ideas for toppings, just look at the picture. If you have any questions, post them!

Step 5: Now for the Frosting

Protect your area: put newspapers down! (this step is also messy) You will probably also want to wear old clothes, although gloves aren't neccesary in this step. Get all your materials set out before you begin because you will want to move quickly: bowl, spoon, spackle (and maybe a screwdriver to get it open with!), pastry bag (here I am using a nifty plastic pastry thingy, which broke halfway through and I moved back to the bag), acrylic paints, and pastry tip, along with your cakes and toppings and wire things. To make the frosting, put a dollop of lightweight spackle in your bowl and add a bit of acrylic paint to tint it (unless you want plain white frosting...) To make a delicious buttercream, add just a bit of yellow. Then, mix it up with your eggbeater until everything is well combined and it looks like frosting. then, spoon some into your pastry bag with tip attached and start squeezing it out on your cupcakes...you will probably want to experiment a little first. This mixture behaves a lot like frosting except it is frothier so it is fairly easy to work with. After putting frosting on, add your topping of choice and stick your metal hanger or card holder in the top (don't worry-the spackle is pretty hard when it dries!)
I apologize for not taking very many pictures at this step...I had to move fast and by the time I was done I was covered in fake frosting!

Step 6: Finishing Touches

One last thing you can add is a drizzle of the sauce of your choice. To make a sauce, mix acrylic paint with water-based varnish (clear) and drizzle on your cupcakes. I made the mistake of also adding water and the spackle frosting soaked it right up so it doesn't look great...but maybe yours will turn out better..
Let everything dry until hard, and you are done!!!
Your creation is now ready to be hung, given away, displayed, or hung from a ceiling. :)
If you have any insightful or inspiring comments, please post them!!
I hope you all enjoyed this and are ready to make some "frosted fakes" of your own.

Oh, and I suppose I should include a disclaimer: any injury or poisoning caused by the creation or consumption of these fake cupcakes is the fault of the idiot stupid enough to eat one!

I have also included pictures of my mini cupcakes, if you would like to see those as well.