Wow. I often wonder when plants disappear like that if it isn't due to problems with the hybridizing. A weak parent plant, or disease prone, etc.
I also wonder since it seems to have never been registered under that name if it is possible that it may have been registered under a different name. Did you ask the folks at Palm Hammock who their source for Frilly Dilly was originally? Maybe they know who the hybridizer/grower is.
Good Luck, I hope you find it.