Well, some great news for me, which admittedly isn't news at all, but still: Kontakt users (and, according to the latest version of Translator, EXS24 users as well), it is possible to use compressed audio for samples. Unfortunately for Kontakt, the compression results in a .ncw file for each sample, which, needless to say, is almost completely incompatible with other audio-related software, but still, Native Instruments claims it's lossless, and I'm willing to chance that in the name of disk space.
So, how much does it compress? For testing, I used my Distorted Reaity CD's, which normally total about 1.5 GB of samples. I used an Akai formatted CD originally, meaning, among other things, that samples are distributed across 30 and 60 MB partitions. That being said, I know for certain that some partitions took up less space than others after conpression. My guess is that it has to do with the overall volume of each sample, as the more compressed partitions were generally ones consisting mostly of percussive samples.
Overall, the compression saved me almost half a gigabyte of space, meaning it took up 2/3 the space it did uncompressed. Of course, this method of saving space will not work with non-Kontakt sounds I have (i.e. Omnisphere), but then again, most of the sounds I do use involve custom Kontakt instruments one way or another.