I give away a large portion of my blog's income to charity at the moment and have committed giving a minimum of 10% going forward. I think you'd run into issues giving the full amount away to charity and publicizing it though as the affiliate networks don't want to disclose payouts to the public and other bloggers (everybody is on slightly different deals).

It's a nice idea, why not just give it a go and go from there. Writing & running a blog is hard work though.