Well, no, it's not mainstream in that sense.
But, the elements I've used are part of a mainstream romance setting. My point was more about looking at what's mainstream, or rather taking what you like about mainstream content, and turning it on its head.
You're only limited by your imagination, and again -- a lot of mainstream stuff wasn't mainstream before. My work on cosmic romance probably isn't as popular now. But give or take a few years, and it might jump. Just like vampires and zombies and what not.
Key thing is to just do what comes natural to you.