Nice buget

EVGA Classified SR-X 270-SE-W888-KR LGA 2011 Intel C606 SATA 6Gb/s USB 3.0 HPTX Intel Motherboard
https://www.newegg.com/Product/Produc...82E16813188119

Intel Core i7-3960X Extreme Edition Sandy Bridge-E 3.3GHz (3.9GHz Turbo) LGA 2011 130W Six-Core Desktop Processor BX80619i73960X
https://www.newegg.com/Product/Produc...82E16819116491

Get two of the above processors.

CORSAIR Vengeance 24GB (6 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 Desktop Memory Model CMZ24GX3M6A1600C9
https://www.newegg.com/Product/Produc...82E16820145350

Get two sets of that for a total of 48Gb of ram

Then stick whatever gfx card (s) you want in the above should set you back about 3 thousand with out gfx cards.

Really for 5k buy whatever you like.
Dave