I was wondering about those. I have one (really for home medical use) and was interested in how it worked at altitude. I know there are some 'aviation grade' alternatives but they look to operate on the same principles? What are the technical limitations of these devices to elevate our present pilot limits of 12,500 to say 17,500? Its a nice place to fly as nobody is up at those alts.His oxygen concentrator idea to replace the pressurization will also go nowhere when he sees the actual technical limitations of doing that at high altitudes.
As for the rest of the NG well that debate is long over certainly regarding electric anything for something weighing >4000#.
At least in the old Moller inspired days we actually had silly concepts that had decent ducted fan pressure loadings. Not to mention cool 'T' tails that at least were big enough to put your coffee cup on when you were outside admiring your machine.