Bo,
28" of draw out of a 52" bow requires some real tillering skill with the best bow woods out there. I have a couple 52" osage bows that draw in the neighborhood of 27" but they've both taken a little set because of my inexperience with short bows. Mesquite is what I use for tip overlays as it's gorgeous wood. I have a mesquite log seasoning, but have not built a bow from it yet so I don't know how good a bow wood it is. I think you're picking a very hard design to pull off with an unknown wood. I plan to back mine with osage and let it bend a little through the handle. However, my bow will be in the 60" range.
So, to answer your question, I have not worked with mesquite except for overlays and I'm skeptical that you can get 28" of draw out of 52" of mesquite stave. Can't speak from experience though.
Good luck,
George
