Tale a look at the Filson Field Bags
http://www.filson.com/232.HTM or
http://www.filson.com/230.HTM, if you are wanting something to go with a nice suit than I might look at the Leather Field Satchel
http://www.filson.com/252.HTM .
Of course if you want something really nice take a look at
http://www.tannersalleyleather.com/index.htm they are a small (about 4 craftsmen) shop that makes really nice stuff. I think they will even make to your design or requirements.