Looks like 1.5TB RAM with 15 cores costs $50K. But it shouldn't be just about RAM. The problems I'm working on requires 250 cores on similar amount of data. If there was an option to get say 150 cores with 2TB RAM, things would fly for sure.
4-6 months and you'll have a Knight's Landing Xeon Phi with at least 72 cores and 288 hardware threads, with vector instructions, and you'll be able to stick 3 of them in single blade.