I had a go at this a while ago (wow, 7 months)
I’ve played about with a sending a block description to a client when connection to a server. It worked, as in I could change the hardness of the custom block. I used JSON to send the block description and the client could register it. As blocks could only be loaded in the Init phase, it registered a stub block, which could have different properties depending on it’s metadata.
This is essentially what Forge Multipart does, so for block information I could try and serialize TileMultiparts into J…
Here’s a JSON file: http://pastebin.com/7kJmKW2R
and here’s the API calls to create the JSON: http://pastebin.com/DePskxPZ
I experimented with using method calling on classes and objects but that would be dangerous so I would recommend limiting it to a finite set of possible actions in the JSON.