Hey man,
Im looking at also building something along these lines. I wouldnt get just SSD's first of all. A) they dont work as well for just plan storage. Anything that is static and doesnt change its actually faster to get a fast HDD. So I would look into a WD Black 6tb or a Seagate 10TB. Also, you cant Raid 0 two M.2 on a x99 motherboard. They dont support it. I would definately get a samsung 960 pro (they just release the 960 over the 950) and it goes up to 2tb on that. You can run more m.2 on a PCIe lane but you cant Raid them. Trust me I looked into it since I wanted to do it myself. The z170 motherboards support it but not the x99. So I would definately put a m.2 in the m.2 slot. Then you have the option to add up to two more if you dont use all the x16 slots for graphics cards. Two Titan X Pascals is the most you can do right now unless you want to go 4 way sli 980 GTX TI. If you go the Titan X Pascal (Which I would recommend) you have space for other things like a Sound card (Creative Blaster ZxR), m.2 adapters, or maybe a dedicated Internet card (Asus 3200AC Adapter). I would definitely just get the two Titan X Pascals, get up to 4 m.2 960 Pro 2 TB (one in the m.2 slot, 2 for the 2 unused pcie x16 slots and 1 for the pcie x4 slot since technically thats what it would go in anyways. Its just compatable with the x16 slots as well) if you want to max out your PCIe slots and then add the sound card. Just make one your bootup drive and the rest storage. Then fill up on HDD (either the WD Black 6tb or Seagate 10tb) based on how many slots you have on your motherboard. Speaking of Motherboard, I would actually switch to the ASUS Rampage V Edition 10. As of this moment I believe it is considered the best X99 Motherboard out there. (about 600 dollars which is what most are that are top end) Also, the case they mentioned is a good one but another alternative would be the Corsair 900D. I'd pick which one you like better as they are both very modular and very spacious. CPU like others have stated the i7-6950x is top of the line unless you go Xeon. For RAM check out the Dominator Platinum SE Blackout or Chrome. There is also a Corsair AX1500i over the AX1200i. Also, check out some RGB fans they are pretty expensive but pretty badass. Corsair has some they just released and thermaltake has their Riing series. Also look into RAM coolers. Corsair has some for their RAM or there are third parties that do it too. Another great way to drive up the price is to water cool it which I would recommend for a build like this. Also look into 4k monitors to drive up the price