There are a couple of questions you need to answer a little more fully before this question can be fully answered.
First: What do you mean by RPG? In the 8 / 16 bit era these were games that had a distinct focus on driving a character through a story, the "reward" for playing the game was that your character would move forward through the events of their adventure. Usually this would be paired with Random encounters and coming from Japan.
But in the modern era everything has character development and story wedged into it (not always a good thing), as well as enough mechanics that are similar to leveling up your character (whether it is getting better weapons and armor, learning new skills and magivc, or actually leveling up) So you have to be clear.
Second: what is "Sci-Fi" or "Fantasy" Shadow Hearts is set in the late 1800's but there is enough spirit magic, vampire-esque tomfoolery to fool anybody in a medieval chain mail recreation. And Bioshock is set somewhere around the forties or fifties but that is science fiction (yes yes yes steam punk science fiction).
Right now I am playing Hotel Dusk on the DS, much more a gritty Pulp Fiction Detective Story with not a single sci-fi or fantasy element in it. Really deep and interesting story and it plays very well. But more of an adventure game than an RPG per-se. I think, if game development is in your future, you might haver stumbled on a potential market there.
What is the deal with this obsession with pirates, fantasy, spaceships, and ninjas anyways? While I admit that ninjas are pretty cool, the problem I have with medieval content with orcs and goblins and wizards is they never really discuss the realities that they did not have toothpaste substituting dental care for chamber pots... a toilet you cannot flush in your bedroom... awesome. Pirates = scurvy, the romantic imagery is somewhat diluted when I consider finger nails falling out, and sci-fi's borderless rules make it so hit and miss that I don't understand why people don't call it out more often.
