If you're not particular for a specific brand, you should check out Marshall's/TJ Maxx, they've always got a great selection on handbags..they might have some great totes, especially with summer approaching.
Tano has some great oversized totes that are reasonably priced, fun colors and well made. I don't know how to copy the pics from the web sites so I will attach links. Also, you can get more information from a TPFer named Tano Expert in the Tano Bags thread. She is also the owner of the web site Musthavebags.com, although neither of these are in her current inventory. I am sure she can help you track down if you have any interest.
Belen Echandia has a beautiful bag called the Stroke Me and come in Chocolate, Petrol, Mottled Gold, Wine and Tan. You would want the Large size for your puposes. These are gorgeous bags and Jackie (the owner and creative director/designer) provides incredible customer service. You can purchase from her web site directly or from Muse Ten in San Fransico.
You should check out the wide tote on myoilcloth.com. I just got mine and I love it. It's nice and big, but light. And it has lots of cool interior pockets and a zip top! You can also check out different colors and the interior on ebags: