Fizzle, I would keep it simple and stick with your focus fabric plus 3 for maximum impact. Also, you said "I am not a great fast finisher and want this to be a finish, so I know I have to keep it simple and on track!"... I think you have your answer!
Just keep it streamlined this time and be easy on yourself. And don't forget to post pics when you finish it!
QuiltE, I think you could get it (and just about anything) to work with the right fabrics and enough deliberation/forethought/judgement. However, I think it would be quite difficult.