@prometheus We have a few hundred AMD GPUs, so we'll be focusing on those. OpenCL does run on NVIDIA hardware, though not very well, so in theory people with NVIDIA GPUs should be able to get at least some hashrate out of our miner. Maybe after version 1.0 we can look into adding CUDA support.
@nimos Definitely Linux, possibly Windows as well.
We're not very far along yet. Right now I'm working on writing a python implementation of Equihash just to make sure I understand the algorithm. I suppose that technically might qualify as a standalone CPU miner, but we won't be submitting it for this contest because I think it would exceed the permissible limit on silliness for the project.