Neither of the projects you linked seem to use 4k panels.
The idea of utilizing landscape panels in angle and using special lens is a logical demand but the 4k per eye is a bit unreasonable since the price of those panels right now is expensive. Somewhat below $10k each. The $150k version is a high-end example, but it does match the resolution you mentioned (or at least almost) and it is actually available. Well, it's manufactured on order to be accurate.
About the flat panels for high FOV, quoting from the infiniteyes oculus forum topic:
"
According to the inventor it's currently not an issue, but he didn't know if that would hold true as screen resolution increases.
At the moment, he says the largest issue with his HMD is eye strain. He believes the main reason for this is because the screens are flat and sitting on your face at two different angles. So, when you turn both eyes to look at something near the edge, one of your eyes will be looking at pixels that are physically closer to it than the other eye, which causes unusual ciliary muscle strain. One eye physically has to focus (accommodate) in a different way than the other eye, which is unnatural. This effect isn't as noticeable in the Rift because the Rift's screen is flat against your face, so, no matter how you rotate your eyes, both pupils are roughly always the same distance from the pixels that you're focusing on.
The eye strain issue might be fixable with a curved screen. He's currently trying to get his project noticed by Samsung. Samsung is sponsoring projects that might benefit from flexible HD displays."
