One of my favorite features of Instacast is the settings for "Skipping Back" and "Skipping Forward" to 5, 10, 20, or 30 seconds or 1, 2, 5, or 10 minutes. That is, pressing the previous |<< and next >>| track buttons skip through the audio instead of skipping tracks. This is very handy when listening in my car (which has previous and next track buttons on the steering wheel that work via Bluetooth AVRCP). It's also handy when double-clicking on the home button and using the on-screen buttons or using the earbud buttons (so I don't have to enter my passcode and launch the app).
The same feature that's so handy for podcasts in Instacast would be very handy when listening to podcasts or audiobooks synced from iTunes. Are there any apps that will play this audio and provide this feature?
I know there is an API to allow apps to play audio synced from iTunes, since I use an app called SayAgain that has buttons to skip forward and back by 10 seconds. But it doesn't re-purpose the previous and next track buttons. (I'd submit a feature request, but I don't see any way to do that on their web site.)