Subbed El Dorado 5 & Flor de Cana 7 for the Appleton, and Trevor Jones 'Jonesy' Tawny "Port" for the Sherry. It's alright, sort of flip-like, but without the richness. I wanted nutmeg, but I want nutmeg with all flips. Meh.
Just reading all of the other comments and tasting notes, this is one that might not stand up well to substitutions. All of the ingredients are so unique...although I do hear the comment about trying a P/X-Amontillado split.