Well, from talking with Ahimoth on btc-e, sounds like mtrlt managed to find a workaround for the issues I was having with scrypt miner kernels on GPU.
Short version... any of my kernels that got speeds like that also got 100% invalids. Yet the same kernel worked fine on CPU or if I dropped global and/or local worksizes to silly small levels... which of course made it dog slow again...
And of course RS turning the whole thing into "OMG CONSPIRACY!!1one"... duh, it's RS.