> I'm interested in buying access to hosts within OWN_IP_BLOCK, anybody have some?
Can this be mitigated? Is it realistic? Will you know how it was compromised?
A primary means black hats use to measure trust for purchases is repeat sales to the same buyer (for differing needs) and maybe some illegal activity e.g. paid via illegal means (to filter out anyone that is constrained to only legal means). Passing those tests is difficult (although possible by professional white-hat-consultants, however white hats want to remain undetected by the black hats so have constraints).
It is also dependent on the price you are willing to pay. Obviously you need to pay the botnet herder more than the sum of: worth of the machine to them, cost of the risk to them due to transaction, cost of sales, their normal profit margin.
If you offer a little, all you will find is bottom feeders and liars - i.e. information value is low.
If you offer a lot, you are giving an incentive to get your network compromised.