Have you noticed that GNUCAP has released a new version in late November! I downloaded it and installed it and it seems as if now can take parameterized spice netlists. Ah, the final frontier is broken.
I made a quick script running N corners on an amplifier in parallel, spawning N different processes for which I included different corners and different parameters. Works quite well. I made a quite ugly script where I got N files which I had to merge and then plot with octave.
You need for example: