Posting this where an AMD employee might see it.
In tracking down a problem with my video card that proved to be bad RAM, I discovered a GPU memory tester written by and for the Folding@Home project. The tester was first written in CUDA, then ported to OpenCL for more general support.
While the code is rough around the edges, it does seem to work. This would be an extremely useful capability to include in the CCC for users and IT to test hardware on a troublesome machine.