without a limited budget you can built whatever, but if you are talking a single motherboard then without entering in details here a configuration, I think the most powerful configuration would using a Quadsocket Pro motherboard with 4x Intel Xeon E7-8890 v2 (7K$ each) (60Cores 120 Threads) 6Tb of DDR3 ECC Ram some old good 4x Nvidia Quadro K6000 (hmm 7K each if I'm not mistaking) that will use them ECC Ram and some PCI-E Drives in Raid 0
I'll leave the storage to your discretion a 1600W Pro Power supply and 4K Monitors, GL HF.