The link below is to an awesome audio comparison of various Portuguese accents:

http://www.learningportuguese.co.uk/audi...cents.html

Does anyone know of something like this for Japanese?

TIA!

Unfortunately I don't know where to find such things online, but we listened to it in class once and it was quite amazing. Real old kyuushuu dialect is almost impossible to understand.

Japanese Pod had miniseries on 新潟, 青森 and possibly one other dialect that I'm forgetting. The dialogues were recorded in both the dialect and standard Japanese, and they explained the differences, so it was quite interesting. You can study various kinds of 関西弁 with this site http://web.mit.edu/kansai/ too, although it's not exactly a rarity to encounter it if you watch TV and stuff. It would be interesting to see an overview of all (or most) of them though.

It's just a bunch of links but many of them seem to have audio. Check the ones with 音声.
http://hougen.atok.com/link/doc/pc/index3.html

You could try youtube. I started reading a book the other day that turned out to be in Hiroshima-ben(at least the dialogue), so I looked this up to see how it sounded

The few dialects I've listened to seem to be less "crisp" compared to standard Japanese. For example, ねがっている would be ねごうとる in Hiroshima-ben, I think. I don't know anything about this subject, to be honest.