Additionally, to replace the headlamps on this car you have to remove the bumper -- at the rate I work, this would be a several hour job.
So after some research, and several "headlight restoration" videos, I decided to try restoring the existing lenses. Basic process is sanding, using progressively finer grits, ending with rubbing or polishing compound.
Rather than buy all the materials separately, I bought a 3M restoration kit, claiming to contain all necessary materials, for about $15. It took about 2 hours total, from masking to final washdown.
Here are the headlights before I started:
During rough sanding (300 - 600 grit):
After rough sanding -- an opaque, frosted look:
Finished -- after rubbing compound. Not clear, still has a milky translucency. But got rid of most of the nasty yellow oxidation, and it's a definite improvement. Probably could have gotten them more clear with another hour of elbow grease and some polishing compound.