To do this in Outlook 2010 is a little more complicated. Yet, it 'can be done'.

You'll need to record a macro first. I cheated and used the code from here: http://help.wugnet.com/office/Button-Open-Template-Outlook-2007-ftopict1083041.html

Thanks Sue as always! Such a legend to the community.

To do this you'll need to have the Developer Tab up and running.
On the ribbon, right click choose Customize the Ribbon.
Under Customize the Ribbon: Tick the Developer box.
Then create and save your macro to open your template file. See above.Once done and saved.

On the ribbon, right click choose Customize the Ribbon.
I created a New Group under the main home tab.
Then From "Choose commands from:" Select Macro and 'move' it to your newly created group. You can rename your macro, but it doesn't seem you can change the icon symbol to your own if you have one, which is shame. That would be useful.

If you get prompted about macro security, change your Macro Trust settings:
File>options>Trust Center>Trust Center Settings>Macro Settings:
I have mine set: Notifications for all macros. You could install Redemption. - http://www.dimastr.com/redemption/ . I've seen others use this. You may or may not be able to do this in a corporate environment.

So yes, you can do it, it just seems there are more steps involved.
Once you've done all your macros, you can remove the developer tab.