I've made a general purpose pie menu component in C# for Unity3D, which supports text items, image items, and 3d object items too!
Here's a silly demo, showing a set of SimCity pie menus:
(If you don't have the Unity3D browser plug-in installed, it should show you a link to install it.)
They have a full set of useful notifiers so you can tightly integrate them with your application to give rich feedback during tracking (for example, modifying the 3D menu items, or previewing the effect of the menu item and distance parameter in real time, making them more like "direct manipulation").
For example, to show how you can implement feedback like The Sims pie menus with the head in the center that looks at the selected item, I've made a 3d object in the pie menu center with the webcam texture on it, so YOUR head is in the center of the menu, looking at the selected item! (That's why the demo asks for permission to use the webcam.)
The pie menu and each item has a title as well as a description. One feature I've added is the ability not only to disable an item, but also to provide an explanation of why the item is disabled! (PacMan in the demo is disabled, for example.) I wish other menus and widgets would do that -- it's frustrating when you can find an item you want, but can't figure out why it's disabled!
Another nice thing about them is that you can either configure algorithmically with an API, or with JSON data (which makes it easy to make dynamic data driven menus downloaded from a server or database), or construct them in the Unity3D editor out of objects (which makes it easier for artists to design them)!
I've made a custom Unity3D editor that lets you edit the properties, drag and drop textures and objects, edit and rearrange the items, and has some convenience commands, so you can place the 3D item objects in a circle in the 3D world, and call a command that figures out which item is in which direction by their position, and tidies them up. (That is much easier than arranging their order in a linear list of items.)
I'm going to play around with more in-world editing features, to make them easier for artists to design them.