4k displays are available for medical analytics now. If my calculations are right Intel talks about 4.6k for 24'' and 5.7k for 30'' (12 megapixel with 24'' and 18 for 30.)
Have to take a look at it before I can decide. I have doubts, too.
EDIT: 4k on a 27'' monitor gives about 175 ppi.
Ciao, Walter
PS: We use the same monitor type, I think ...