It seems like there could be money to be made in this as there is deffinatly a demand for it.
Being the clever type

I thought of doing this but then thought about the customer base. Let's see what we got. Tight arsed, cash scrapped wannabes who'd probably just rip the audio and flog it on ebay for a pound ago

. So left it!
On the other hand, what I did do was record myself reading out aloud feedback questions and then stating the correct answer. I listened to that for months on end, and I think it worked!