Hmm, this might seem familiar to you, but 8 months ago I wrote this.
This program checks if the translations files are up to date with the English ones. It then builds a database and a textile file with this data. People can then see what pages are not up to date and can work on that.
I know it's python and there are a few things that I should work on (using docopt if not nice if you are not running debian jessie), but I think it would be really nice to add this feature to amber. Without it, some pages can be reaaalllly outdated and nobody will know.
If you are still interested to implement this, please let me know. I can work on it a bit more and do mofications to make it easier to "port" to ruby if you want.