ORC is part of Octane and has been for months, so I suggest you give it a shot if you haven't yet looked into it. The payment page will soon be public (and based entirely on OB/hr) once the new OB bench is released with Pascal card support in the coming weeks. Until then you can use ORC testdrive - PM FuzzyBro and he can get you set up.
I do think ORC is going to be cost effective probably right around the point where 20 (high end) GPUs aren't enough. That being said, you can always do multi-frame job renders on an infinite unmber of GPUs locally, and that is how ORC works for max efficiency. We will definitely re-examine the network render limit after see how headless rendering, AMD cards, and 3.1 affect stability.
We have Enterprise tier of Octane out in the wild for validated GPU boxes (like VCA) with Linux and 10GE for max stability. You can talk to our BD team (
[email protected]) if that is something you might be interested in.