We would love to add support for JSON but, currently, all of our resources are tied up with cart/billing issues and a massive migration of our primary server/storage cluster.
However, this is something that we can consider adding in Q2 of 2011.
Although, if you (or anyone else reading this thread) is able to provide a JSON-based output (using our XML as a guide), then we could easily put something like this in place in the next couple of months.
FYI... something like this would be implemented as a free value-add and not as a paid feature.
Thanks for the suggestion.