I am developing on spare time an "all web languages" homogeneous collection packer in order to speed up client/server interaction specially for database results where the column name could be considered as a key and each field in the same column as a row.
As example, the host where I put the initial test does not allow more than 50Kb as uploaded data, this means that without JSON.hpack is not even possible to consider to move 5000 of rows.
The reason it could be faster is that JSON.stringify, the good old Douglas Crockford version, is not that fast as we think ( not comparable with native IE8 JSON.stringify ) and if the given object is smaller, obviously data to parse is less as well.
Here you can test the first JSON.hpack test page.
The project is not hosted yet so to know more about the simple API please read the incomplete (code speaking stable though) source code.
I wonder how many people would be interested in their favorite server side language implementation, I can create the PHP, Python, and C#, but I am looking for Java, Ruby, and if possible other languages as well. The logic truly simple so it is just a matter of time ... anyone fancy to contribute?