Thanks! There are some libraries like PCL http://pointclouds.org/ for use with Kinect cameras or things like LSD SLAM and OpenDTAM available for desktop for real time processing and some other structure from motion solutions to reconstruct models from images. They are all really cool, but can be a bit clunky to use for people without computing background, so we're trying to create a new solution that's a bit more mobile and easier to use, hence the iPhone app. Give a try to the sites I mentioned though, maybe you can find something that fits your needs.
Yeah, I'm at the point of running Agisoft Photoscan under wine, no results yet. But of course I won't get the heat-map quality indicator, which is the bit I really like about your app!
Good luck, hope you manage to make it work! Thanks, that's the advantage of having it run real-time. Unfortunately, I don't think there is any other out-of-the-box solution right now that can give you this sort of feedback with a normal camera.