A post on Al Dente explains how you can make cupcakes that are shaped like pumpkins. To do this you need special pumpkin pans like the ones from Wilton - see here and here.
Wilton's mini pumpkin pan makes four realistic and adorable mini pumpkins, using whatever kind of cake batter you wish. For my first round, I chose a carrot-cake batter and frosted them with orange and green cream-cheese frosting. I also like the idea of making a spice cake batter and plan to try that out on Wilton's larger pumpkin cake pan. And, of course you could use quick-bread batter as well and do pumpkin-bread pumpkins!
Like most cupcake pans, the mini pumpkin pan holds the equivalent of half a batch of cake batter. It has eight compartments, which, after you put them together, gives you four whole pumpkins. You may want to note that this means if you give a whole pumpkin to someone, that means they're eating two whole cupcakes. You may want to consider this before handing a whole one over to a toddler. Trust me.
Handing an entire pumpkin cupcake over to a toddler will result in a very happy toddler and a large mess. Kids will truly be thrilled if you are able to build one of these pumpkin cupcake patches.