The huge bow on this tote may make it not truly work appropriate, but I thought I would post anyhow because it's large, but not too large, comes in a variety of colors, and is vegan. I particularly enjoy the 10" drop of the straps -- the bag will sit nicely under the arm. It's made from cotton, polyester, and metallic fibers, and is available in the pictured black, beige, pink and yellow. $168; available via Nordstrom here.
Beckon makes a similar bow clutch, which also comes in the same four colors (the beige is pictured) and is made from the same vegan fiber mix. It's $98; also available via Nordstrom here.