What about something like this?
http://www.thessdreview.com/daily-news/latest-buzz/samsung-begins-mass-production-of-industrys-first-m-2-nvme-pcie-ssd-for-pcs-and-workstations/
or
http://www.legitreviews.com/intel-ssd-750-nvme-pcie-ssd-review_161829
Both address the write performance needed I believe and are getting cost effective. Wit the NVMe capabilities the latency and queues would be awesome.
Intel SSD750 about $1K for 1.2TB storage.
There are others entering the market too like...
http://www.gskill.com/en/product/fm-pcx8g2r4-960g