61mm is the clearance available, Noctua NH-L9i and Cryorig C7 both qualified for it.
One 4K monitor is already very hard to drive even with the latest Titan X Pascal (barely hit 60 FPS in most of the titles), and you want 3 to 6 (all 4K?)?!?!

That's a serious gaming showcase plan you got there 

Nope, C7 fan is not "flippable" so pull config is not possible.
1080p (Full HD) monitor is a better choice instead of 4K in this case, this is because if we take three 1080p monitors as example, you will get a combined 5760 x 1080p ultrawide triple screen setup already, and this is an insane resolution to drive, you will probably need at least two GTX1080/Titan X Pascal running at SLI configuration to make the most of out it.

Budget wise, yours is ok, 20K (max) is still a healthy budget for this "crazy" setup 

Mostly aesthetic and better heat dissipation (just slightly).

Example of metal backplate on a GPU, it looks much nicer right? 


Intel Core i7 6700K - RM 1550
Asus Z170 Pro Gaming Aura - RM 772
Corsair Vengeance LED 16GB (8GB x 2) DDR4 3200MHz RAM - RM 618
Asus GTX1080 8GB GDDR5 Strix (x 2) - RM 6418
Kingston SSDNow UV400 240GB SSD - RM 315
Seagate Barracuda 1TB HDD - RM 205
EVGA Supernova 850 G2 - RM 659
Corsair Hydro H100i V2 - RM 561
Dell UltraSharp U2417H (x 3) - RM 2907

Total: RM 14005 (ETech price inclusive of GST)

I haven't go into "all-in" mode yet, Dell U2417H is chosen mainly because of its super slim bezel which is good for Nvidia surround setup (triple monitors setup), the downside is slower response time (6ms) and 60Hz (still a standard anyway). As for GPU, GTX1080Ti is coming very soon and should be packing with Titan X Pascal's performance at much cheaper price tag than Titan X Pascal (est. RM 4500).