I’m half tempted to buy a few hours of highcpu AWS compute power and get
  it done nowish instead ... I set myself a $50 spending limit, which
  gave me about 24 hours of compute on an instance with 32 virtual cores

The price of a c3.8xlarge with 32 cores and 60 GB is currently $0.28 in us-west-2.

You could get 178 hours of compute for your $50 budget.