Hey Jeff, thanks for the mention!

I haven't seen 404 pages done like this before, which is why I wrote about it. Sounds like Andrew has done something like this, and I'd actually love to see what he's doing (I'm guessing he couldn't give us the details without using the "H" word :) ).

As to use in other template files, while I think that 404 pages are the most generally applicable and easily implemented examples, I also think private pages could be used in other places as well. I'm hoping this will spark more creative people to come up with even cooler uses of private pages.