I'm not sure this list is entirely fair. Granted, everything on it has never been publicly released, but I think there's a big difference between something that was merely announced and something that was actually prototyped and functional but never made it to mass production.
There are a lot of things that can go wrong in bringing a product to market and actually designing and producing a few units is 9/10ths of the work and the hardest part of the job. To call those projects pure vapor is an insult to the engineers who worked on them.
Thus, I think there should be a difference between vapor announcements and products that never quite made it to market (IE, prototypes exist).
Also, many of those items, especially some of the Commodore ones (CD32 030 board, 2631) were never even announed - they were internal engineering projects that got canned due to bankruptcy and idiot management well before the public was supposed to know about them.