[vezzy-fnord]

The most protracted piece of vaporware in history is actually Project Xanadu, at a whopping 54 years.

[gpvos]

Is someone actually still working on that?

[vezzy-fnord]

Yes. In fact, OpenXanadu was unveiled this year: http://xanadu.com/xanademos/MoeJusteOrigins.html

That said, it's mostly just a web reimplementation of the incomplete 1998 Udanax client.