A year or so ago I built this (you need a modern browser- Firefox, Safari, Chrome, etc.):
(copy-paste the link in your browser, as the forum won't let me paste a direct link as I'm a new member)
Then I kind of forgot about it, and today I realized that I should probably show it off.
The source code is freely available under the MIT license (basically you can do what you want with it as long as my name is included with the license) here:
It's still incomplete (notably lacks export capabilities), but I figured some motivated person somewhere might be willing to contribute to it at some point. Or maybe I will if I find the time
Last edited by Guillaume on Fri Apr 13, 2012 10:06 pm; edited 1 time in total