OK interesting, I didn't realize that the altcoins use scrypt. I remember hearing that Litecoin used a scheme that was supposed to be GPU-resistant, but didn't realize it was scrypt.
They very specifically only handle the very weak (1024, 1, 1) work factor parameterization of scrypt (which AFAIK isn't used by anything other than altcoins) and various workflow optimizations they do internally make them unable to run even those scrypt parameters on arbitrary data.
