The new Tree Widget might become a great time saver when building prototypes containing typical navigation systems.

My main issue: I want to import my existing navigation / information architecture of excel (or other spreadsheets)

Could you imagine a import dialog or some kind of Copy-Paste to create a tree widget?

You might have a look at Treejack by http://www.optimalworkshop.com/ 

It allows me to translate the copied text into a working navigation tree with ease. Although there is no linking and it’s a one-way solution. Which does not matter to me.

In the same vein, I would like to see this widget tie in with my Axure site map structure - could we add an option to add 'Page reference' (same as with flow shapes) in order to update the name according to your site map and link through to that wireframe?

We also need to be able to set a width on the tree widget - at present I can't make it fit my default navigation width because i can't wrap nav items onto two lines :( 

Thanks, Luke.

Options to be able to wrap the lines and control the width separate from the width of the text in the nodes would be great. Would an accordion widget work better for what you are building or do you need more than one level of child nodes in your navigation?

I too would like to see a way for the Tree, and/or the Menu, and eventually an Accordion-like menu control, to be automatically populated with the Site Map links.

A better granularity of control might be to match a Menu node with a specific Site Map node. That way, you can leave out "utility" parts of your site map that are not part of the normal user experience.