Basically such customization can be done. However, you will need to change the default ControlTemplate of the RadTabControl. You can find steps, describing how you can extract the default ControlTemplate of the control in this article
Once you extract it you will be able to implement your customizations. Please keep in mind that such tremendous customizations of the default templates of the controls are out of our support. This means that we will not resolve or support issues that may occur after the customization.
Pavel R. Pavlov
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