I've seen competition archers use a high elbow. They shoot fairly low-poundage bows that are fairly long by hunting standards. I think they're even coached to do that, but I can't tell you why. The problem with a high elbow with a short, heavy-weight hunting bow is that your index finger gets smashed down on top of the arrow nock, which can hurt after a while, and can cause the arrow to bend down. The arrow rebounding from this bend makes it difficult to tune, and hurts accuracy.
I don't understand what you mean by having to draw past the corner of your mouth if your forearm is in line with the arrow. Why can't you just stop at your normal anchor? Is it because your draw length is less that way? I think your draw length should be determined by your form, and not vice-versa.
I think you should decide where you want your head to go when you shoot, such that your shooting eye is over the arrow, and it is a natural position that you can repeat for every shot. For many people, that means keeping their head in a neutral position, but bending slightly from the waist so your shooting eye ends up over the arrow. You should bring the arrow up to your anchor without moving your head to accomodate the arrow. I think the key is to find a head position that works for you that you can repeat every single shot.