Today I merged the AMD split kernel work that Cycles master has to my own repository (and along with that a whole slew of fixes and improvements for Cycles in general). From the next Rhino WIP build on it should be possible to render on many AMD GPUs.
Note that the OpenCL work is still work in progress, not everything works yet, but the devs responsible for this work have it on their todo list to enable everything eventually.
I’ve posted a short screencast of it in action here (and it shows that in OpenCL transparent shadows don’t work yet):
Enjoy and happy rendering,