Is there a systematic theology resource based solely on the words of Jesus? Numerous Bibles have a "The Words of Christ in Red Letter" feature. Understandably, there is some debate concerning which verses and words should be in red (but this question is not about that.)

This question is: What is a good resource on systematic theology that only looks at the verses in red -- i.e., instead of being based on the entire Bible, is based only upon the words that Christ says?
I'm pretty sure that there is no source that looks at only Jesus words. However there are certainly theological approaches that place a much greater emphasis on Jesus words. For a start you might want to look at Red Letter Christians, a group that attempts to redress what they see as an imbalance in North American Evangelicalism, which they believe has seriously de-emphasised Jesus' words in favour of Paul's writings and selected Old Testament teachings. However the members of that group do pay attention to other parts of the Bible, and do treat them as inspired and authoritative.