Agree with this. Hit up department stores and check clearance racks. Also I found this, don't know if it's exactly what you're looking for, but the reviews do say it's a slim fit.
Zara has great trenchcoats, both long and shorter styles.
I love this one.
Big thanks to all of you for the suggestions! I've been seeing a lot of shorter trench coats lately, which I like. I'll have to get out to the stores this weekend!
__________________
"Delta Chi is not a weekend or once-a-year affair but a lifelong opportunity and privilege"
- Albert Sullard Barnes