UPDATE: Purchased an iRiver H120 jukebox/recorder.
So we're getting closer to appropriate recording solutions on the iPod 5G (with video). Apart from the drain on battery life, Griffin's soon-to-be-released (and iLounge-tested) iTalkPro looks quite promising:

Griffin iTalkPro Stereo Microphone for iPod 5G | First Look


Will it replace MiniDiscs and cassette recorders for rehearsing musicians? It does sound like the ideal podcasting tool, including for those types of “soundseeing tours.” It could also be a very interesting device for fieldworkers, including ethnomusicologists and ethnographers.
True, there are other recording devices out there. And, yes, iRiver tried that route (full-quality uncompressed sound) for a while. But chances are that this one will work. Not necessarily because the iPod is such a success. But because it's well-integrated, all the way through “post-prod.”
You got your iPod at rehearsal, or in the field. Your press the record button and get a clear reading of how long you're recording. So far, pretty much like any other digital recorder.
You then go home, plug in your iPod into your computer. iTunes imports the tracks, with timestamps and all. From iTunes, you can manage those tracks like people manage pictures in iPhoto (and it does work on both Windows XP and Mac OS X). You can encode these files as MP3 or AAC (or other formats, with plugins). On Mac OS X, you have those tracks available throughout the iLife software suite, including GarageBand (which became a decent tool for podcasting). In GarageBand, you build your podcast or other audio presentation using the iPod-recorded tracks. With iWeb and a .Mac subscription, you can even publish that presentation as a podcast directly. Who could ask for more?
Well, ok. A lot of people. First, we'd need more control on the recording settings. Automatic Gain Control is fine for voice but doesn't make much sense for music, at least for music that isn't constantly loud. And then, “low gain” and “high gain” aren't enough control for most people. Not to mention that you can't adjust left and right channels individually. And, of course, you can't use professional microphones directly without adapters which have their own issues. As for iTunes to manage tracks, it's an interesting solution in many respects, especially with grouping and such. But it's not really meant as a full-fledged database for archiving recordings. Then, though GarageBand seems to be a very enjoyable piece of software, it has its own issues.
Still, with any number of flaws, the iPod->iTunes->GarageBand->iWeb->.Mac seems like the ideal solution for different kinds of people.
Actually, a good user base for this type of technology is in the education field. Went to a presentation on podcasting in university teaching offered by Université de Montréal's CEFES teaching center. Through this kind of technology and method, instructors are now able to provide content in a convenient fashion and focus face-to-face classroom interaction («présentiel» as CEFES members tend to say) on actual discussion. An important effect of this is to get people to understand that teaching isn't the transmission of information. In such a perspective, recording different things for pedagogical use needs to be efficient and seamless. Sounds like the iPod as recording device might become just that.

Ah, techno-enthusiasm…