I read with quite a bit of interest the new idea from Ming Thein: the Ultraprint(1).
The idea (if I understand well) is to make a print that, independently from the viewing distance, is so dense that the human eye can't resolve the dots (given that we have a minimum focusing distance...); more or less a "Retina print", borrowing from Apple terminology.
This leads to a thing around 720 (real) PPI on print, which means that for this kind of prints you need 36Mpix for a 10x15" print.
The photos and crops on the page looks really nice (especially the red tree).
Would this kind of prints reopen the megapixel race (if it has ever stopped)? Do you think that the idea could be worthwhile?
(1) I am in no way affiliated with this site. Just a reader.