I would love to see The Black Robin portrayed in an anime-style movie/show, whichever fits the length better. I would say Disney-esque movie, but I would worry about them butchering the story to make it more "family friendly." It's kind of fairy tale like, but that includes darker elements like what Disney is know for cutting out of their other fairy tale stories.
On the other hand, I think RomaMates would make for an interesting dating sim.... Four eligible men struggling to find love, each with their strengths and downfalls. My guess is Dewi would be the most popular character in a dating sim situation, especially since he's willing to go really far to make his partner happy (he'll become the person they want him to be).