Well, my natural negativity says this isn't likely to happen. Which means nothing, of course.
There's no doubt that Miller would be far and away the best QB on campus the moment that he arrives at Alabama. Could Miller/Kiffin/Bama offense get in sync with just fall practice? Would he come with anything less than a guaranteed starting job from Saban? Would Saban have enough confidence in him to give such a guarantee (Saban would never give such a guarantee, you say.... ? Think carefully about that...)