Dan, actually this sounds pretty yummy! Prunes have a bad rap, they are only dried plums and delicious properly dried. The Cynar and lime juice read like they hit the right notes, and I like the arrack and rye backbone. I'm gonna try this!
Just made it again tonight for the first time in a long time. Those little cans of prune juice have been littering up the refrigerator long enough. I tried it with both 1/2 and 1 full oz of prune juice and was happy with it as written. My wife didn't like it when I made it last time, but came around this time.
You are right prunes. A favorite ice cream of mine is "dried plum armagnac" from Lizzy's in Waltham, MA. Do you think it would sell as well a "prune brandy ice cream?"