Hey all! I posted a thread about this design several months ago and have now finally almost finished it. There are a few more area's to tweak and a 'new', framework feature (a dynamic, collapsible footer with Flickr integration and a newsletter subscription submission form) to add yet still, but I thought I'd go ahead and link to what there is so far and see what everyone thinks.
The only other person I've seen doing this is forsaken which he implemented very nicely. And I agree the use of imagery is a nice touch and most importantly a space saver. Forgot to comment about the use of images and I agree with kevin that is a nice touch to the style.
XF just uses the "extra.tabs" class for additional tabs and then pulls in the text wording for whatever that may be. In this case, there is only one image for the extra tabs. I will include a package of custom images but one will probably have to manually edit their addon nav templates to assign separate images. I may look into adding a style property setting to make this easier.
I'd agree to a degree but a few little colour changes here and there would transform the blandness your speaking of, I was just curious to know what areas you found bland.
Issue john which is affecting you notices. when you expand using the toggle sidebar when having multiple notices they overlap onto the next notice. This is something we had to fix on our custom sidebar toggle which affected notices just something you may want to look into.