Currently, several private GPU miners are used to sell cloud hashing.

http://toom.im/ has the fastest known GPU miner, while

https://cloud.zeropond.com/ was the first to offer cloud hashing (unavailable to US customers).

The release of a good public GPU miner is one of the contest goals. Another is to close the huge gap between the reference CPU solver, which achieves 0.06 solutions per second, and private CPU solvers, which achieve 2 solutions per second (all single-threaded an a high end Intel Core i7).

A public CPU miner is essential for launch to be considered valid in my opinion. Any coin instamined at a huge advantage by a small audience is doomed to fail.

I'm pretty sure that both CPU and GPU have been developed and I would be very surprised if the competition didn't include an optimised CPU miner - guess we'll find out tomorrow when entrants are released

I wouldn't be surprised if we see some early submissions with a whole host of updates leading into the final contest hours. My fear is that there will be a number of last–minute submissions on the eve of the contest closing.

Either way, if you know OpenCL or CUDA, you can probably land some easy money here.