Ned,
Im also a great fan of citrus Marmalade. This site has some interesting variations.
http://www3.sympatico.ca/mwhitcombe/marmalde.html
Let me know if anyone has a source for Japanese Amanatsu citrus?
I love the Korean marmalade. Its called Yujacha. Yuja is yuzu and cha is tea.
http://www.asiafood.org/yujacha.cfm
Its a little confusing. Koreans sometimes call Yuzu Citrus = Yuja Citrus. To complicate it more they call Yuzu Citrus a Citron. So its also called Citron Tea.
I have found this brand in a local store.
http://www.lotteplaza.com/product_images/09192006145456_591_full.jpg
I like it very much. The tea is a delight and eating the slices of rind at the end is great. I also put in on eggs, pork, chicken, toast and etc.
I did make a marmalade with the Shudachi fruit that was on the tree I got from you at the Expo in Aiken, SC. I used the Yujacha recipe. I will definitely make more next year.
Terry