Here is a collection of samples I've written in the past few days to answer your questions from the MSDN forums, etc.  I hope you find these helpful - keep the questions coming!

How can I intercept the mouse down on a ToolStripGrip?
How do I use Table layout with ToolStrip?
How can I clone a ToolStripMenuItem?
How can I use ToolStripManager.Merge?
How can I implement IDeviceContext?