You don't have to worry about getting pen on these bags. They are made from chalk board type fabric that you can personalise using chalk. I saw these bags a couple of season's ago in Paris at Tranoi.
The designs are by a couple of friends Luisa and Tine, and launched only a couple of season's ago. I love the stripped back style of these bags. They are part vintage influenced but also explore new and interesting materials and material combinations.
You can see the rest of their range here: http://www.tl-180.com