A quick google search turned up http://www.mobilepodcaster.com/ which is somewhat similar. What's the killer feature that sets your idea above this one ? Also, what are your ideas for an impressive demo of this idea?
The capability of giving anyone a monetization channel. Mobile Podcaster is really good, but its just a recording/publishing app. The main features they have is to add intro and publish directly to WordPress. There is no editing to add commercials or ads that can monetize your podcast. Also the feature I'm talking about should be from the listener to the producer (not the other way around). So if I listen to your podcast and I want to advertise my site in it, I just select a "free space" on your episode and record myself or upload my ad.
As a related aside, it's often possible that the software you want exists. It's extremely tiresome and boring and frankly awful to weed through and try them all out.
As an example, I tried to find some good RC helicopter simulator software recently. Horrendous. Top scoring links are talking about software from the 90s. Stuff like that.
Solve that issue and you'll probably do really well.