Ask HN: Best 4K IPS monitor for an array of three displays?

Lately 4x1920x1080 hasn't been cutting it. With four HD displays, it feels crowded and fragmented. So I've started changing over to 4K displays on a GeForce GTX 960 with 3 displayport interfaces.

The 4K world is still expensive, but the on-screen real estate and seamless environment is worth it to me. And after trying my luck with TN displays, I'm ready to pay the extra money for IPS to have a viewing angle that isn't so confined and high-glare.

I want to have three 4K IPS displays in portrait orientation side-by-side. I've been seeing more and more of that setup, and it seems to work best for what I do.

I'm looking for an affordable IPS ( In-Plane Switching ) display with an optimal resolution of 3840x2160@60hz.

Does anyone have any pointers on brands, models, and vendors for this sort of thing?