JSYNC is brilliant!
It's a brilliant idea: bank on JSON's popularity and more widespread implementations, add some of the important YAML features not present in JSON on top of it. The result is JSYNC, along with its preliminary CPAN module. (I'd probably picked a different name and choose something like "\" for prefix instead of ".", but hey, it's not my project :-)
A few months ago I was really desperate with the YAML situation in Perl. We have the largest number of YAML implementations, but none of them are good enough compared to Ruby's libsyck. I even contemplated converting all my YAML documents to JSON, but of course that plan was cancelled because JSON doesn't even support references nor objects.
Here's to hoping JSYNC will rocket to popularity soon enough. Ingy++.