Very interesting idea. It might also be interesting to see an ad block, similar to Google ads, with relevant scriptures or quotes. I can think of two site that you could probably tie into to get the data.
The first is mine, Scripture Tag (http://www.scripturetag.com). It is built around the concept of keyword tagging of the scriptures. I have not built a full API, but each tag is syndicated via RSS and I am sure I could feed you any pieces that you need.
The Second is Connor Boyacks Quoty (http://quoty.connorboyack.com). I know Connor has an API for pulling out quotes on specific keywords so it you may be able to pull in that very easily.