I would pay too. Blender users are a big part of Octanes clients, and I think they were much present in the early age of Octane developpement.
For my own, I have discovered Octane because a member of the early Octane Team invited me to test Octane by a PM message on Blenderartists.org.
I don't regret at all, because Octane render actually improved a lot my images, but it also required a heavy investment in hardware (high end graphic cards, RAM, Cubix box, Router and network extension) and software (switch to 64bits OS, Antivirus license for network extension, Third party software for camera animation).
I think that many Blender users who had before Octane no other choice than the Blender Internal render also invested much to use Octane. Today, there is Cycles, that can use the hardware purchased initially for Octane, but it is not yet as mature and fast as Octane. There is no doubt that it will improve fast, but for what I have tested so far, Cycles material setup system is imho a bit tedious, and I would really prefer to continue using Octane as my main render, for everything.
So, I would really want a Plugin for Blender. I know that there is a compatibility problem with the conditions of GPL License... and I hope that a solution will be found.
French Blender user - CPU : intel Quad QX9650 at 3GHz - 8GB of RAM - Windows 7 Pro 64 bits. Display GPU : GeForce GTX 480 (2 Samsung 2443BW-1920x1600 monitors). External GPUs : two EVGA GTX 580 3GB in a Cubix GPU-Xpander Pro 2. NVidia Driver : 368.22.