Is it possible to have an icon/toolbar based way of selecting whether files are viewed in icon/list/detail etc modes?
NT
Yup, enter Customize mode and drag stuff from the Customize dialog, Commands tab, View category to your toolbar. The ones you want all start with "View In..." and are near the buttom of the list.
There's a button for this already on the default toolbar, in case you've overlooked this. It's a drop-down button with a little bike icon on it (bike = cycle, ie cycle through view modes - well Trevor obviously thought it was clever 
)
I think it's clever too.
[11:50] i am verrr verrr drunk