Anyone know any good AU stories that are based in a more science fiction universe?

Purity by Knight of Disorder
They were created, artificial beings. Or perhaps genetically modified children. They were made to be weapons. One did just that, hunted and killed like a wild animal in a war zone. The other far too young to do so, neither with any control.
Rating: MA - Universe: Alternate - Status: Complete - Category: Chapter Stories - Genre: Action, Romance - Updated: 04-23-12 - Created: 03-27-12 Chapters: 12 - Reviews: 34 - Words: 30,889 - Reads: 15,279

I have't ever actually read one that was in a truly science fiction, mine really only reaches into it from time to time.

This is the first one of the top of my head, but I really enjoyed it.

A Cross of Blades (Rated R) by Striking Falcon

dokuga.com/spark/story/1200/1

mediaminer.org/fanfic/view_st.php?id=47364&submit=View

Kagome! Where are you? By Jeffs is the closet thing this to science fiction I know of.
Kagome and Sess are transported through words by a magical cub and they must learn to work together to get home. Includes Worlds like Lord of the Rings. Definitely Rated MA (Or X and Media Miner)

Inu no Waskei (sp?) Sessh is the next in line for the throne of the Canis system, his parents believe he needs a wife based on an old tradition. Kagome is the daughter of the planet leader of Earth (Terra) and is forced into being Sessh's fiancé. Inuyasha characters with Star Trek setting. On fanfiction.net.