Hi Greg,
I concur with those who suggested you should build the machine yourself.
It is not difficult and can be done in an afternoon.
Suggest you start by looking for the best quality motherboard with the
specifications you require. For example, most at the moment are built
around the Intel Z170 Chipset.
The Gigabyte Ultra Durable range might be a good starting point to look -
http://www.gigabyte.com/mb/100-ud/Model
http://www.gigabyte.com/mb/100-ud/Durable-Safe
Then pick a CPU with the right price/performance point to match the motherboard socket.
At any one point in time, there will be a sweet spot which you can
ascertain by looking at the PC suppliers price lists.
32GB of DRAM.
SSD, hard drives, etc.
Consider two identical hard drives mirrored in a RAID 1 array for redundant
reliability.
Then pick a good case. High quality with slide-out disk storage bays and
plenty of quiet fans and removable filters.
Add a power supply.
You can always add a graphics card with GPUs later if need be.
The motherboards all come with manuals that have diagrams of the various connectors.
Once the motherboard is screwed into the case using the standoffs, the cpu goes
in easy enough (it comes with its own install instructions) and the DRAM just snaps
into the sockets. Which cable plugs into where is the only task that requires any
concentration and most of the time the plug types and sockets are unique enough that
it is difficult to get any swapped. The octopus of cables from the power supply has a multitude
plugs but it will become self evident which plug into the motherboard and which power the SATA drives.
In the end you will end up with a system with the best components (you chose them) and the best bang
for your buck and one that you know was assembled with care.