I'm working on rewriting the code for Spydon, an addon designed to provide feedback on the addon comm channel. So far, I have it using its own window for a message frame that supplies a hex view of all data it catches. While not fully implemented, I also added a feature in the base code to let it record the entire call stack of outgoing messages and the call stack of registered prefixes for incoming messages. This is done by storing the contents of the call stack when SendAddonMessage() and RegisterAddonMessagePrefix() are called respectively. If anyone has any other ideas of what they'd like to see added in, I'm open for suggestions.