I'm no expert, but I don't think it's the right time of year to find transplants. Usually around November is when I've been told is a good time to plant citrus. Also, for a graft to be successful, I believe it has to be done in the early spring, when they get the first flush of new growth.

If you're doing it for the fun of it and learning experience, I'd say go for it (there's a lot of good books or internet articles out there on grafting) but if you just want the tree, it will be so much easier to order one online or from a local nursery. I could be wrong but I think that tree is pretty common to AZ nurseries, especially in the spring. Like Leslie said, now isn't a good time to do this though.

If you really want to try it, here's a good video on grafting:

Grafting Citrus

Ok, so no one knows of a good nursery around Phoenix to buy rootstock from?

You can buy any citrus tree and it has/is a rootstock (even the little 10$ ones at home depot). You can grow one yourself too from suckers from an existing tree.

Generally the rootstocks that growers use are bought wholesale or started by themselves as seedlings. (You can even use a 2 inch plant as a rootstock.. called micro budding citrus)

Ah, great idea. Thank you! I'll tell her that. I think she wants to do a cutting from her family's tree mostly for the feels. Good thing the trees out of Yuma tend to actually list the root stocks, that will make it easy to find one of the cheap trees with an appropriate root stock. If it is just a $10 project, I'm sure the YouTube how to will be fine for her.

Thanks, I had no idea what to tell her.