You have a good point, Chaz. Anyone who listens to ALL the shows has a lot more free time than I do.
Maybe tagging is a good idea (if that's possible. Is it?)
The trouble with trying to organize is that a lot of our podcasts contain lots of those various genres -- R&B, garage old and new, rockabilly, often in the course of one show. I know mine, The Big Enchilada, does. I also do hillbilly shows every few months and often do sets of various styles including gospel, jug band, Japanese punk, "world garage" etc.
Most of the current podcasts have playlists on our Hideout blogs or at least descriptions of each episode.