Hi,
Main requirement: I am looking for a solution that would work with XL 2000
and above.

1. Is there a way to add any kind of activex control (eg: a treeview
control, or even my own custom activex control) to a toolbar with Excel.
Can it be done through a COM-Addin?

2. And what about these 'toolbars'[?] you can see in the Visual Studio .Net
IDE, the ones that you can dock on the sides; they show as a tab, and when
moving over they pop-up; when leaving the poped-up form/toolbar, they hide
and only show as tabs; you can also pin them so they stop hiding when leaving
them.
Any way to use these ones in Excel?
I have made a useform that approximately simulates the same behaviors,
but it 's too far from perfect.

3. I haven't read much about it but it seems like MS Visual Studio Tools For
Office could help, but: 1) i am not sure 2) it only works with XL2003 and
above, am i right?

Thank you,
Sébastien