I just did a clean install and now I am getting a

Clean Operating System install?
You need to do all the major updates before the driver will install properly.

GPU Missing - Ready to start (0.195 CPU's + 1 NVIDIA GPU)
in the tasks list.
Very odd....

Right click on the Desktop, Display Settings, Advanced Display setting, Display Adaptor properties, at the top in Adaptor type does it say "Nvidia Geforce GTX 1050Ti" or just "Microsoft basic display adapter?"

I just did a clean install and now I am getting a

Clean Operating System install?
You need to do all the major updates before the driver will install properly.

GPU Missing - Ready to start (0.195 CPU's + 1 NVIDIA GPU)
in the tasks list.
Very odd....

Right click on the Desktop, Display Settings, Advanced Display setting, Display Adaptor properties, at the top in Adaptor type does it say "Nvidia Geforce GTX 1050Ti" or just "Microsoft basic display adapter?"

Um, I can think of only one, did you get the video driver from Nvidia or Microsoft?

If from Microsoft, go to Nvidia and get a driver from there, try and do a clean install.

If from Nvidia, I'm lost.

The cards are very capable of overclocking easily and the fans to an OK job at cooling them but to achieve longevity of the cards is my ultimate goal. Also it will give me a good grounding for when I build my QUAD 1080 Goliath.

My suggestion, given the rumours that GP102 based Titan might include HBM2, would be to hold the phone, unless you have so much money that it doesn't matter :D

Honest question (not snark): since 750tis are not high end cards, why would they need water cooling? Or, to put it another way, why would anyone make a water cooling plate for it? Wouldn't the market be awfully small (like just OP)?

You are correct that 750Ti's arent exactly high end cards currently, but the idea of a bit of an engineering challenge to get them crunching that little bit harder appeals to me.

I have also thought of setting up a Peltier/Water Cooling hybrid just to see hat is possible.

Did you overclock them enough that fans can not keep up with heat generation?

Honest question (not snark): since 750tis are not high end cards, why would they need water cooling? Or, to put it another way, why would anyone make a water cooling plate for it? Wouldn't the market be awfully small (like just OP)?

Everything I can find suggest it's a driver issue.

I'd suggest trying 344.11 as that's what I was running on my system when it had Win7 on it with no issues at all (or at least something not so recent, say 358.91).
And i'd go for a clean installation, selecting just the driver (you only need PhysX for games).

PC Case Gear and Ebay.com.au have the Thermaltake Core X9 E-ATX Cube Case listed for arrival here by the end of June.

Cheers.

So I have been piecing together my ultimate crunching machine and have come up with the following. Any thoughts or ideas as to substitutions for parts etc would be appreciated.

That would have to come with one terrifying price tag.

I'd suggest looking at a cheaper LGA1151 3(or 4) * PCIe*16 slot motherboard, 16GB RAM, 2*SSDs, i7 6700 (or 6700K) CPU.
The money saved could go to some GTX 1070 GPUs. Even with their current ridiculous prices, with the above cheaper MB & CPU & SSDs they'd probably end up in the same price range as your proposed system, but pump out more work & use less power.

The best of the best of the best is nice, but paying an extra 40-50% for an extra 5-10% performance just isn't worth it IMHO.

These are what I would get, otherwise your list is ok.

Case: Thermaltake X9 Cube Case(Comes in Black or White)
Video: 4-EVGA or MSI GTX 1070 Hybrid cards(980 Ti's are more expensive to run, and 980 Ti's are possibly more expensive to buy too)
SSD: 4-Samsung 850 PRO 512GB SSD(My friend SciManStev uses this, nuf said)

Oh and welcome to the Seti Forums, on Tuesday there is an outage to do maintenance on the data base, which also makes the forum inaccessible for a few hours(4-12 hours, depending on what has happened, nothing to be alarmed about really, stuff happens and the staff knows what they are doing).