Monero isnt profitable for mining because the nethash and difficulty rised 3 times.
If you need " cpu rig " , multiple boards with multi cpu support you can have blade servers like c7000 HP or more particular the AMD opteron
16 core cpus . The model is BL465c supports dual 16 core cpus the whole chassis handles 16 of them so 32 cpus in total in 10U rack space.
There are still some qty in ebay and amazon i think but its expensive machine for my pocket.