I'm already using a 30" monitor; there aren't a lot of 4k monitors >30" that aren't full TVs (50-60"). Going to 4k at 30" just increases my DPI with no increase in area, and I'm already not using tiny fonts; more DPI isn't what I want. I'd really like 4k at 40" or so: that still bumps me from 100 DPI to 110 DPI, but I get a lot more usable screen real estate. Unfortunately, the market for monitors over 30" is tiny / costly.