Crumble the baked and cooled pumpkin bread into a large bowl, and work it gently between your fingers until it is in small pieces.
Add the frosting to the pumpkin bread crumbs, and stir them together until well-combined and no streaks of frosting remain. The mixture should be moist and hold together if you squeeze it into a ball between your fingers. If it seems too dry, add another spoonful or two of frosting to get it to a workable consistency.
Use a small 1-inch candy scoop or a spoon to scoop out small balls of the pumpkin bread mixture. Roll them between your palms until perfectly round, then place them on a baking sheet covered with parchment or waxed paper. Chill the balls for 2 to 3 hours or until firm.
Place the orange candy coating in a medium microwave-safe bowl and microwave it until melted, stirring after every 30 seconds to prevent overheating. Use dipping tools or a fork to dip a pumpkin bread truffle into the orange candy coating. Let the excess drip back into the bowl, then place the truffle back on the baking sheet. Repeat until all of the truffles are dipped.
Melt the chocolate chips or chocolate candy coating in the microwave, and stir the melted chocolate into the remaining melted orange coating to make a deeper orange color. Transfer the dark orange coating to a paper cone, piping bag fitted with a small round tip, or a plastic bag with a small hole cut in the corner. Pipe intersecting lines across the top of the truffles to represent the pumpkin's creases.
Melt the green candy coating in a microwave-safe bowl, and transfer it to a paper cone, piping bag fitted with a small round tip, or a plastic bag with a small hole cut in the corner. Pipe curls of green coating on top of each pumpkin to represent vines. Refrigerate the truffles briefly to set the candy coating. For the best taste and texture, serve Pumpkin Bread Truffles at room temperature, and store extra truffles in an airtight container in the refrigerator for up to 2 weeks.
Elizabeth LaBau is a cookbook author, recipe developer, and avid sugar enthusiast. She is the author of The Sweet Book of Candy Making and is the self-appointed chief sugar officer at sugarhero.com, her blog where she shares creative, modern, fun dessert recipes. She's also the candy expert at about.com, and her work has been featured in many national magazines and newspapers.