Finally got this workstation completed, it took me very long time to get all pieces together. Lots of components I waited to show up on ebay, like DDR4 and SAS cables. I missed a chance to get DDR4-2666, but 2400 will do, and if I was more patient there are now E5-2673 QS which look awesome...
So this is what I got:
Asus Z10PE D8 WS (bios 3304)
2 x 2698 V4 QHZD
128 RDIMM (8x16)
2 x LSI SAS controllers (IT passthru-unraid and raid one)
2 x NVidia 1070 (sli)
1 x Samsung SM961 NVMe SSD (boot)
and bunch of other disks on these LSI SAS controllers
(and old 40" 4k Philips from previous configuration)
CPUs and SASs and DDR4 are from ebay (used). Other components are new.
All worked from the first try. Motherboard can handle all variety of hardware I plug in and I am impressed that this all works 100% stable 24/7 for days considering these are ES A1 chips.
Cinebench R15 benchmark should be between 4200 - 4300, but I had there were 4 vmWares running in background, so result was somewhat lower.
One remark on ASUS mobo, when cpu gets warm, bios doesn't push fans to max dynamically (yes using PWM fans), but instead I need to set speed in bios. After having insane amount of features in bios I don't understand how they missed this one, hopefully they will add it...
Anyway, I can happily confirm that these ES chips work well even if mobo is overloaded with all kind of PCIe cards. Thanks to ASUS to support these ES toys and stable mobo.
I hope this helps someone... Also thanks everyone in this thread for their posts, it helped me to take the decision (first time ES) otherwise I would never have budget for workstation like this if I had to go for retail chips and new SAS or memory.
PS: for those who wonder why LSI and not Intel SB, well, copy speed in windows is between 500MB/s to 1.6GB/s on LSI, while Intel is dropping speed terribly when doing simultaneous operations (e.g. multiple vmware)