Three question marks
Is there any way to switch workbooks, now that ctrl + tab has been overriden?
You can always go to view > switch windows (xl 2007) for a list, but that is pretty inconvenient.
I don't have 2007, so mine's under Window.
Maybe an extra shortcut such as ctrl shift tab would be a good addition? Is there any other native xl shortcut?
I had CTRL+SHIFT+TAB to go backwards through the view history (same as ALT+TAB & ALT+SHIFT+TAB in windows)
I don't know of any other native shortcut (apart from CTRL+TAB) and couldn't find one just now, but adding it through code would be extremely easy. In fact it might also be good as a Combo dropdown box as well (though it'd just be duplicating the menu... except that it could remember previously opened workbooks and open them again as well. Sort of a combination of Window + Recent File menu).
Do you have a preference for a Key Combination? I'd lean toward CTRL+ALT+TAB.
I think the ability to remember recently open WorkBooks in the current session is a good idea (I could never see the point of restricting it to 9), and a KeyPress to navigate through that list could work in a similar fashion (so that it's not scrolling but rather choosing)