Have a quick scan on youtube for "infochannel". Scala currently lives on as a Windows application.
As to memory protection, I personally prefer not, because IMHO it slows things down (AFAIK the OS has to broker all memory requests and check every one is legal = many more cpu cycles used per memory access) and to an extent it encouraged better code (you have a bug that brings down the entire machine often = nobody uses your product) - that is of course a pretty uninformed, IMHO view and I do appreciate that's a huge security risk in this day and age.
Regard it being a realistic approach, I see it as a market a new entrant could compete well in. Using Wintel for this sort of thing (as EVERYONE does atm) is fraught with problems and usually results in an unsatisfactory solution for the customer. A low-cost simple to deploy and use box, that can form a network of such boxes without configuration - and importantly generate an impressive looking end result - would I think become a de-facto standard and would get used everywhere. Think of the days when Amigas ran cable TV and digital signage everywhere because they were the cheapest and simplest machines to do it on - while actually having the capability to do it.
With visionary hardware design such as that of the original Amiga, this little display generating box could then worm it's way into other markets as the parent company made money from actual sales and the hardware made it's way out there in volume.
Coming in with the latest greatest computer (and therefore competing with windows) or games machines (with Xbox, PS3 etc) with the best will in the world is just never going to work - so I think something a little more subversive like this is required.