Mac Pac make brilliant packs in a variety of sizes and styles. I have a 40L hiking pack that I use for travelling. Its extremely light with an excellent harness.
I also have a smaller 25L pack which also has a really good harness and hip belt.

Something like this might be in the style you are looking for.
http://www.macpac.co.nz/packs/trampi...g-daypack.html