So basically, the SD upscales of the Felisher cartoons on the Blu-ray Superman Anthology boxed set are still my best bet? I guess that since they're in the public domain, the cost of doing a proper restoration just isn't very beneficial?
I've really gotten spoiled at this point and just de facto expect Blu-rays to have lossless audio. I was shocked to find 128 KBPS audio on The Searchers or 650 on The Dirty Dozen.