This morning I visited Roger & Shirley Meyer in Fountain Valley CA to purchase a Green Sapote (Pouteria viridis). They have 2 or 3 dozen plants about 3 years old in 5 and 15 gallon pots. At $35 each for the 5 gallon pots I just couldn't resist -- I came home with three! You can contact them here:
XotcFruit.