Best solution = learn how to graft and choose a suitable rootstock. Alternately, purchase trees with the appropriate rootstock for your needs or find someone locally that has experience with grafting.

Another possibility = air layering. The success of this method varies with different apple cultivars. It works great with some and not at all with some. The biggest disadvantage is probably the lack of ability to choose a suitable rootstock.

BTW, rootstocks can be beneficial for many many reasons including influencing:

1. ultimate size of your tree
2. growth rate
3. amount and complexity of maintenance
4. ease of harvest
5. productivity
6. preciosity
7. senescence
8. hardiness
9. adaptation to different soils and soil conditions

10. drought tolerance
11. how well the tree will be anchored
12. whether the tree will need permanent or temporary support (not just how well it's anchored)
13. fruit size
14. resistance to certain diseases
15. resistance to certain pests
16. rootstock and scion graft compatibility
17. tendency to sucker
18. and I'm sure I'm leaving off at least something.