Dream computer (or console) game mashup?

I'm self-aware enough to know that I always want more, more, more when it comes to my PC games. (I'm personally rubbish at console controls, but I don't knock gamers who do play consoles, so I'm asking this question to ALL gamers.) What would be your dream mashups for games?

I play a lot of RPG and simulation games (among other, more casual games), and I would LOVE to see a mashup of The Sims and Fallout. I would love to see the The Sims building tools, social interactions, open game play (no "end" unless your last household member dies), item gathering, DNA-based families, and generational play ... with Fallout open-world exploration, combat, desperate survival, post-apocalyptic setting, resource gathering, and rich NPCs. My dream mashup would include being able to have large households and community settings, or to be able to go it alone if the player chooses.