If you have gone so far with System.Windows.Forms, you gone too far. :-)
You should switch to WPF where the content model (http://msdn.microsoft.com/en-us/library/bb613548.aspx
]) is so liberal that such things are more than natural.
Why pushing the limits of Forms and almost abusing it, when a switch to WPF will give you a very regular use of the feature?
How about that?