What svm python modules use gpu?

There's a GPU-accelerated LIBSVM that uses the CUDA framework.

scikit-svm will never support GPU. From the FAQ:

Will you add GPU support?

No, or at least not in the near future. The main reason is that GPU support will introduce many software dependencies and introduce platform specific issues. scikit-learn is designed to be easy to install on a wide variety of platforms. Outside of neural networks, GPUs don’t play a large role in machine learning today, and much larger gains in speed can often be achieved by a careful choice of algorithms.

ThunderSVM A Fast SVM Library on GPUs and CPUs

It also provides a scikit-learn Python interface