My vote is for a Geraldi Dwarf. Mature size 6-8ft tall and spread. Berries are excellent and bear longer than most. I wouldn't think there would be much mess because it's more like a shrub with no canopy. I just planted 1 bareroot from Burnt Ridge Nursery, and the little thing already has a couple fruitlets. In fact all 3 of my mulberries have been in the ground less than a year and all have fruits forming. Great low care fruit trees! Oh, and try Burnt Ridge, Edible Landscaping, or Whitman Farms for Geraldi.

Good luck,
JB