Clay Graham:
This is one reason we would like to create a client side plugin for the TOR browser. Any ideas how this would be done?
What is the Tor specific question here?
I think this is a normal Firefox question "how to create a Firefox Addon? or do I misunderstand? Just make sure your Addon goes through Tor and does not create a Tor Browser proxy bypass.
There are a few Tor/proxy related Addons in Mozilla Addon. I'd read their source.
https://addons.mozilla.org/en-US/firefox/search/?q=Tor&appver=10.0&p...
Or is you specific question how to get your new Addon installed by default in Tor Browser?