A short report on minor progress:
I've prepared a new version of recaller that now uses AAC ADTS instead of ADIF. Recordings now play well using VLC, so this should take care of the compatibility issues mentioned by others. Unfortunately, the Maemo Autobuilder is down once again, so I can't yet build the new version for you. Hopefully tomorrow

I plan to add FLAC support as an option.
I might well change to (or add) a statusmenu function like the one in the example code, might be handier for some. AA full app might be another project.

However, for now it works well as a general purpose recorder, as this example cleary shows: I went skiing with wife and kids today. In the afternoon, Forgetful, I put the N900 in my pocket in unlocked state, touching the recaller widget by coincidence... 1.5 hours after, when checking the time, I saw the recording reminder popup! Therefore, I'm currently listening to a 90 minute live recording of my family's skiing adventures . The sound is extremely clear, I can hear all conversations we had on the slopes, probably up to 10 meters away, while the phone was in a trouser pocket.