Coolest high-end folder (demountable)? PennyFarthing Dan's Fold-up.
Yes, you can buy one. Yes, riders fly with these to far-off cycletour destinations and rallies.
I don't see how the spokes were tensioned up. Not by truing via each spoke. My guess is each hub flange can rotate with respect to each other, hence my seeing long levers employed, because the tensioning up was instant.