Jeroen Bakker aka atmind has releases a proposal for speeding up Blender's compositor using OpenCL. He had also talks with Ton Rosendaal, the chairman of the Blender Foundation, about his proposal. So this is a really serious commitment. To fund the project, atmind has started a Fundraiser. By donating to the project, YOU can help out make this a reality (yes, I also donated). To get development started, $500 still need to be raised. So if you'd like an ultra-fast compositor in Blender, chip in!
Btw: He has already created a working prototype which he demonstrated at the last Blender Conference in Amsterdam. Check out the massive speedups below: