nothing new except the type of memory -- special memory cards and embedded OS have been around for 20 years to boot and run the os ...
~15 years ago even you could buy a passive backplane 486 system with 16 systems in one case - each on a card with no hard drives, now you can buy the same thing with p4s (but active backplanes)
I read about this as well. I remember hearing a story about somebody who got to play with a computer that had a ram drive as the system drive. He said it was the fastest computer he had ever used - everything was instantanious - and this was on a very old Intel system.
For 60 bucks sounds like something that would be fun to experiment with...