While OpenCL cannot access the framebuffer directly, there are provisions for interop with OpenGL buffers, textures etc. It also has several interesting features that will likely show up in OpenGL 3.1+, like shader binaries, multithreading (e.g. loading a buffer in the background) and reference counter objects.
Amd, Nvidia and Apple have committed to supporting OpenCL, so the question when this support will arrive. Are you interested in this development? Any plans to use OpenCL when it becomes available?