We made our own TabControl/TabPage, which are derived from Microsoft. The TabControlDesigner has a section with two 'Hyperlinks' to add and remove Tabs from the control. How can we modify/extend this functionality? By default, the original TabPage from MS will be added.
I don't think the TabControlDesigner was written to allow adding custom tab types in mind. The TabControlDesigner type itself is internal and the logic that adds a TabPage type is also hard-coded.
Syncfusion to the rescue! Our XP TabControl that is part of Essential Tools will let you easily specify your custom tabpage type that is to be added in the designer via custom attributes. Note that we closely modeled our tab control API to resemble the .Net TabControl, so that it will be easier for our customers to migrate from the .Net control.