Victor Oliveira, our GSoC2011 student, is going to continue his work on getting OpenCL support in GEGL for hardware accelerated rendering and computations. AMD got interested in the project and agreed to sponsor it.
The plan is to implement GPU-side color conversions and compositing operations, as well as some basic filters. Victor is also planning to create a simple API for development of new OpenCL based filters for GEGL.
Currently estimated deadline is March 2012. GIMP already has an optional GEGL based projection rendering as well as an experimental tool to test GEGL operations, so hopefully we are going to see some exciting performance improvements soon.