The Internet's Finest Tropical Fruit Discussion Forum!"All discussion content within the forum reflects the views of the individual participants and does not necessarily represent the views held by the Tropical Fruit Forum as an organization."
Would be a long drive for you but Atemoya nursery in Vista has a lot of nice rootstock.
Cherimoya seeds are pretty simple to grow. You can start them now and have some of the fast growers ready for grafting in April if you use a greenhouse.