Despite this, I suspect it may have some healing qualities similar to an unrelated plant that also has saponic glycosides in it, as well as a bitter principle, which, I read, grows in South America. The Zulus and others use that plant for various purposes.
http://www.plantzafrica.com/plantklm/momordbalsam.htm

I would like to try to grow Poncirus. The seeds are said to be most viable when first taken from the fruit. Does anyone know of a nursery that sells self-rooted plants or the whole ripe fruit?

http://davesgarden.com/guides/pf/go/55494/

And this site sells seeds:
http://www.mishobonsai.com/poncirus-trifoliata-japanese-bitter-orange-p-89.html

You might want to try posting this on a citrus thread too, probably get more hits. I post my plant requests in the California gardening forum and people are usually very knowledgeable regarding where to buy plants in my area. Good luck!

It is the only citrus-like plant I can find that would be hardy enough for my zone.

Also, we have enough "wild" cats in our area that I think the birds might appreciate one cat-proof tree to nest in.

The fragrance of the blossoms is not supposed to be as strong as in orange trees, but the flowers are supposed to be a bit larger, and it is supposed to be attractive to bees as well.

I am hoping it also has some medicinal qualities that would help the bees.

I would use it as a partial barrier at the back of my garden.

Here's an interesting variant of Poncirus with a contorted shape, still with fragrant flowers and apparently vigorous growth.

I would really like to get a normal Poncirus if I could, though, as it would probably grow a bit larger. I saved the link just in case...looks like an interesting site as well.

Actually, if there were any hybrids with oranges or lemons that were frost-hardy, that would be even better, but I don't think the hybridizers have gotten it to that point yet--unless they're just not reporting it. Seems they would be...trade secret?

We have made such progress with things like chrysanthemums, one would think a food product would attract a great deal more attention. Of course, the life cycle is much longer, though.