The mono blocks are mostly for ease of loop routing and convenience. That way you don't have multiple blocks to connect to and install. You aren't going to see any benefit as to OC'ing with a mono block vs individual blocks. You don't usually see EVGA blocks since the X58/SR-2 boards because EVGA is such a small percentage of motherboards sold VS Asus and the like that most manufacturers don't see the ability to profit from making them. We have been lucky to have a forum member (nateman_doo) that has been our go to guy for mono blocks when there was enough demand for them but I don't know what his last big project was on them.

On one side monoblocks cut number of fittings and tubing required while looking really nice (for the most part anyway).
 
On the other monoblocks are absolute pain in the back when you want to swap CPU (faulty or as an upgrade). You have to remove whole board. Unscrew everything, replace CPU and re-seat the monoblock again.
 
Me personally, prefer separate blocks for everything than one solid piece of kit. There is also no cooling benefit from using one approach or another.
 
There are two approaches to monoblocks. Something called FCB (Full cover block) by Bitspower. Its a set of blocks (3 or 4) which together form homogeneous whole - if you need to replace CPU, just have to remove two pieces - top cover and CPU block. Advantage of this system is that technically you don't even need the top cover and can connect blocks separately as usual. On the other side is for example EK. Monoblock is solid piece of metal/acryl/POM. To replace CPU total dismantling of the motherboard loop is required (that includes VGAs and memory block if used). With some monoblocks (like offered for X99 Asus WS by Liquid Ecstasy) you have to take extreme care when seating it - its big lump of heavy cooper and it has to align perfectly. Another crazy idea is monoblock for Asus Rampage 5 Edition 10 from EK. To mount it you have to drill the holes (EK manual) on 2011-3 mounting socket - basically you make  motherboard worthless and void every imaginable warranty procedures because of physical damage to the PCB - which for any vendor is Auto-Null&Void-Warranty clause.
 
I don't agree that VRM blocks are only worthwhile for extreme overclockers. Take Classy X99. I've cut 20C between standard heatsink and using Bitspower block. Right now my OC 5930 VRM hovers at 38 (while with radiator it was often hitting 60C when temperature outside skyrocketed). Especially in cases with not enough airflow or built for quiet operation VRM block is a no-brainer.
 
 
 
 

zophar
You aren't going to see any benefit as to OC'ing with a mono block vs individual blocks.

Can I safely assume a system with water cooled VRMs will run more stable with higher overclocks? My plan is to get an i7-7700k and try and get it as close to 5.0 ghz as possible.  Would you say this much of an overclock will require more than air cooled VRMs?

http://www.performance-pcs.com/bitspower-thor-eix99-nickel-plated-full-covered-block-clear.html
there is a huge thread about using this mono block on all of the evga x99 mbs in the x99 section.