Find a local nursery and they will order some for you.
Iterations are fine, we don't have to be perfect
My 2nd Location:Florida HardinessZone:10 AHS:10 GDD:8500 Rainfall:2in/mth winter, 8in/mth summer, Soil:Sand pH8 Flat
Bareroot rootstock planting season is still about 10 months away, but you can order bundles of 10 each of the apple, pear, and plum from Fedco (http://www.fedcoseeds.com/trees/?cat=Rootstock). As for citrus, I have no idea.