Well, after a hiatus of several months (sorry) I've finally finished the plugin for serial control of Denon receivers, as well as a .gml and basic .ccf to go along with it. I've only tested this on an AVR-3803, but I've implemented most everything in the latest release of the serial protocol fom Denon, so (hopefully) it should function for pretty much all of them. I would think that with minor modification it work with the latest models with an ethernet connection as well, but I haven't been able to test this.
I've tried to make this as organized and user-friendly as possible (my goal was to put together a package a newbie can drop into their setup and have up and running pretty much "right out of the box". This is my first plug-in so I'm sure there are a few things I neglected to consider, so please post any requests or construcive feedback and I'll see what I can do. I'd also appreciate it if people would post their success or failures with different models of receiver.