Have you tried writelatex? They are rolling out features and partnerships like crazy. There's a solid free offering and a pro tier

Here's a referral link so you (and I) get more space for free: https://www.writelatex.com/signup?ref=64cf3f9ff138

BTW - lots of start-ups here in London trying to innovate around academia and research. Here's a post I recently wrote about the scene: http://freyfogle.tumblr.com/post/99273943690/thoughts-on-fut...