However, it gets even better because... even if someone has ported a GPU miner, the N-factor (separate from difficulty) is about to increase on May 14th, (as I understand) creating a sudden condition where CPU miners have the advantage over GPU miners.
The May 14 change from scrypt+chacha(32,1,1) to scrypt+chacha(64,1,1) doesn't cause any sort of situation where CPU's will be faster than GPU's.
As explained by the YaCoin author, each time N increases GPU miners should take a hit, slowing them down while CPU miners are unaffected. CPU miners are further benefited by a slight drop in difficulty, while N hits the GPU dudes hard.
It'll slow them down only long enough to open a text editor and tweak cgminer's OpenCL source file for a different value of N and restart cgminer. Anyone that modified the OpenCL source to switch to scrypt+chacha/keccak very likely already parameterized N at the top of the source so it's a 1-line tweak. At some point (around N=256 or N=512) the modified cgminer users will be slightly inconvenienced when they need to take a few extra minutes to further tune the lookup gap and thread concurrency.