I have never wished iOS could be skinned more than when I saw this the first time. I think it'd be so cool to walk around with System era Mac OS on my iPhone. Of course, it will never be that pixelated, but I love the retro feel and familiarity of something long gone.
I hadn't seen that project before, but the old System 7 on my 1-bit black-and-white Mac screen was the first thing I thought of. The flat monochrome and pinstripe were things I missed for years after I stopped using that system.