I discovered a wardrobe hole: a midweight summer jacket for our cold summer evenings.

I want something I can shove in my bag in the morning and wear on my way home. That means it has to be fairly casual, but not too casual for my style. Wool, cotton, or a synthetic if it's the right one. Many of my interesting tops have structured shoulders or sleeves that won't work under my biker jacket or cardigans, so a main requirement is loose shoulders/sleeves to fit the tops that don't work with my other jackets.

One inspiration is this drapey Zara trench:
http://www.zara.com/us/en/woma.....66544.html
but I'd want something darker gray.

This Uniqlo coat is pretty cool but a little too outdoorsy for my look:
http://www.uniqlo.com/us/women.....arka-08666

Or this lightweight Helmut Lang wool jacket that just sold out in my size on Gilt:
http://www.gilt.com/look/women.....7cfc3db759

(I do have a men's black denim jacket with big bulky sleeves but it's very unflattering with most outfits. Maybe I should make that one work, but I want something one level nicer.)

Any inspiration? I'm looking for ideas I haven't thought of.