There is a lot of public domain audiobooks and short stories out there. For instance LibriVox.org.
It would be relatively easy to use such audio as basis for short "podcasts".
I have some experience with radio and could be interested in making something like that.
With high compression in mp3 or AAC you can get a 15-minute primarily voice piece down to about 2,5 MB.
This would eat up a big chunk of a days data transfer. But if only sent every two weeks it might be okay?
What do think of this possibility?