In the next version the RotationLocked functionality will be available.
About the XWidth, YWidth and ZWidth properties - we aware of this problem and looking for ways to fix it. But for the moment - yes they should be equal.
Thanks for the feedback!
PS: Another scenario where the RadCube control is used is in the transition navigation in our Snowboard Shop Silverlight example
. The transition is visible when switching between "Products" and "Home" page.
the Telerik team