Isn't Banyuls a candidate? It strikes me as a lovely sweet red wine, beloved with chocolate.
Answer From Expert Roger Bohmrich MW
Elaborating on the question about options for sweet red wines, fortified examples such as Ruby, Late Bottled Vintage and Vintage Port are prime candidates and can be easily found in retail stores. There are French fortified sweet reds (with less alcohol than Port) based primarily on Grenache such as Banyuls and Rasteau that can be absolutely fantastic, but they are not widely available. All these fortified styles are indeed fabulous matches with chocolate, which can easily obliterate delicate dessert wines. Wines produced from native American species (v. labrusca and v. rotundifolia) provide interesting choices in semi-sweet or sweet reds, including those based on Concord across the Northern U.S. and Muscadine in the Southeast. Fruit wines - blueberry or blackberry - might also satisfy a red wine drinker with a sweet tooth. If you search on the Internet, you will find both small wineries offering these types that may be able to ship to you directly and retailers who stock at least a few of these wines.