you need to find yourself some standard rootstock. i'm not sure what is commonly used, but you can't necessarily just buy another fruit tree and graft onto that since it's most likely already grafted. unless of course you can get a fairly recently grafted plant where the graft is higher up on the truck and you can cut the scion off below the graft. then you can do you own grafting using cuttings. grafting is best done in the spring when the rootstock is active, but the scion is still dormant.

Asians don't typically attain 'tall' stature. I've got several on standard Harbin pear(P.ussuriensis) rootstock, and at 12 years, they're only about 8-10 ft tall - and I've done no pruning to control size.

If you're going to graft one, I'd recommend OHxF 513, P.betulifoliae, or P.ussuriensis.