You can use round surfaces as well with the system I made, as long as as the markers themselves are flat. And you can use Frame Markers as well, which isn't possible with the Multi Target system at the moment. Have a look here: http://ar.qualcomm.at/node/2001030
You can use 3D objects that are made up of multiple image targets, so each face must be planar and feature-rich (e.g. a cereal box). Read up on Multi Targets in the Dev Guide.
You can use round surfaces as well with the system I made, as long as as the markers themselves are flat. And you can use Frame Markers as well, which isn't possible with the Multi Target system at the moment. Have a look here:
http://ar.qualcomm.at/node/2001030