Bill Gates' love of the tablet is well-known. It's believed to be the reason Microsoft stuck with the Tablet PC even though it never garnered big sales. What few remember is that years ago, Gates had a vision for a handheld tablet that would be right at home in the market today.
The epitome of that vision was demonstrated at the WinHEC event in 2005. Gates took to the stage and demonstrated a mockup of a 6-inch tablet codenamed Haiku. The tablet was thin, fit comfortably in the hand and was shown "running" Windows. It was only a mockup, as the hardware at the time wasn't up to the task of actually producing one. Even so, it was a very advanced look at what was to come years later.
I had the good fortune to hold the Haiku in my hand back then, and it impressed me. Gates' vision for the Haiku saw it weighing a little over half a pound. The mockup showed it displaying Windows, but a mobile variant to better work on the device was part of the vision.
Sadly, Microsoft never pursued the Haiku even after hardware evolved enough to make it possible. The company moved on to promote the Origami, which was as good as could be done with the hardware of that time, but that fell far short of the Haiku. Now that Microsoft has jumped into the tablet space, maybe the Haiku should be considered.
Windows 8 is designed for such a device, although that small of a screen would be a tight squeeze. But if you look at the photo of the Haiku mockup above, you can easily see such a tablet having a shot with consumers. It might not be what they think they want, but they'd certainly stop and look at it in the stores, unlike the bigger Windows 8 tablets that aren't selling now.
Even the codename Haiku is cool, and when you look at the mockup closely you can't help thinking this thing could sell today. It would make sense to expand that screen to at least 7 inches to work better, perhaps. Windows 8 is certainly the version of Microsoft's OS designed to crack the tablet market, and I believe the Haiku would have a better shot at doing that than any tablet currently being produced.
In 2005, the Haiku was remarkably ahead of its time. Looking back, it's downright impressive how much it looks like the iPad mini that came years later. Maybe Apple was paying close attention to Microsoft.