The Kickstarter campaign initiated by Pimax raised the US$200,000 funding goal in less then 2 hours, so the company is now expected to ship the first models in February 2018. The 8K headset comes with dual 4K displays and can be pre-ordered for US$449, while the 5K version integrates dual 2560x1440 displays and costs US$349.
https://www.notebookcheck.net/Pimax-8K-VR-headsets-coming-in-February-2018-for-as-low-as-US-449.249576.0.html