Honestly, the 50,000 word requirement was never particularly challenging for me. Oh, sure, it takes a certain level of willpower to get myself to stick with the story long enough to reach my word goals every single day, but I'm a fast typist, and it only takes me about an hour to write 2,000 words. But the 2k-a-day (with 5 throw-away days) is a comfortable amount for me, and manageable on the days when I REALLY don't feel like writing, so rather than increasing the amount that I require for myself, I try to make it challenging by doing things like writing in unfamiliar genres and styles, or doing a challenging plot, or NOT allowing myself excessive word-padding, or trying to create something that I think is actually well-written as well as lengthy. Your idea is also nice. I try to make a habit of drawing on a daily basis anyway, so that DOES sound kind of fun, although I would worry that it would maybe feel more like two SEPARATE challenges. But hey, if you started it up, I'm very likely to take it on anyway, because I'm obsessive like that. :P