If you're not comfortable building your own, I'd start with a workstation from Dell or HP (e.g. "Dell Precision Workstations"), choose the smallest amount of RA

If you're not comfortable building your own, I'd start with a workstation from Dell or HP (e.g. "Dell Precision Workstations"), choose the smallest amount of RAM they offer, then buy RAM yourself to get the amount you need (make sure the base machine supports that much RAM). Dell and HP always massively overcharge for RAM upgrades compared to the cost of buying it yourself. In general you can't put a dozen processors in a server. You could get that many cores with something like two eight-core Xeon CPUs easily.