Do you mind fusions? This one features a Hogwarts-Battle School up in space, so it is certainly AU beyond the norm.

http://www.fanfiction.net/s/9603488/1/Welcome-to-Battle-School

If you're looking for something more natural, I honestly don't have anything else that I would call a recommendation in good faith. More of a troll response;

http://www.fanfiction.net/s/8473843/1/Chance-meetings-can-diverge-even-Fate.

 

It's from Ender's Game. Basically it's a Hogwarts type place that teaches space fleet tactics to children/adolescents rather than magic.

 

Went through my old favorites and it's likely you've read these but here ya go. Mostly guilty pleasures at this point.

The Power By Darthbill

So Sue Me By lunakatrina

Control BY Fatpunk

 

This story is much better, Syao. Vincet has a 4/5 rating in the DLP library, and Anarchy doesn't like it. So, with his heavy critique skills, watch the master of writing at work.

https://www.fanfiction.net/s/9652275/1/Bonfires-at-Midnight

 

If I thought that story was good enough, I would have posted it here myself. Notice it's not in the WBA either. I've never considered myself a 'master at writing' but I am always striving to improve my work (though I'm not saying I'm successful at that, either).

 

I can think of a few things that you're doing wrong off the top of my head - things that might not be obvious. I'm on IRC, though, so just pm me or something when you're available and I'll go through it with you.

 

Any other suggestions? I'm in the same predicament as Syaoran.