Can I set a time limit on a voice memo?

My church has been using an iPod Touch to record services which I then turn into podcasts for people who missed the service. This has worked perfectly when I am at the service. However, on the days when someone who is a bit less tech-savvy than I is the person recording the service, there is a problem. Inevitably that person forgets to STOP the recording at the end of the service. In these situations, it seems that eventually -- after a day or two -- when I go back to the church to pick up the the iPod, the battery is dead and NOTHING has been recorded. Or rather, the recording has not been saved. Usually the recording is listed (with the correct Start Time) but the recording length is 0secs. and pressing Play does nothing. :-(

My theory: the person who did the recording never stopped the voice memo app, it recorded for many many hours until eventually the iPod's battery died. I'm wondering if there's any way to either (a) preset the voice memo to record for, say 2 hours (plenty of time for a service which is usually 1 hour) or tell the voice memo to turn itself off after a certain amount of time with no activity (once the service is over and every clears out, the room goes silent)

Any ideas? Are there any other voice recording apps which may have these functionalities?

Thanks for any help.

Peter