With the Silverlight controls we distribute the source code of our themes, this should be a good starting point.
We also provide styles for the default controls as well, but they must be applied explicitly, by setting the telerik:StyleManager.Theme property.
This is the fastest way to achieve a consistent look.
The brushes for our themes are either in a shared file or at the beginning of each resource dictionary, so changing just the colours of a theme should be straightforward.
Currently we have a Windows7 theme but unfortunately no Cosmopolitan.
All the best,
the Telerik team
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