Thank you for writing.
You can add any visual to the hub tile if you customize its control template. The control templates are embedded in the assemblies so in this case you need to open the Telerik.Windows.Controls.Primitives.dll assembly with Just Decompile and extract the control template for the hub tile you want to customize.
Also, since you are a customer, you should have access to the source code of the controls which contains the xaml files with the control templates for all controls.
Please write again if you have other questions.
the Telerik team