I run an original d12 RPG system.
So far, we're calling it the Incunabuli System. It's the Coast's home RPG, built specially to support as elegantly as possible gameplay befitting the setting. It's based on the sweet, consequential parts of old school design, but it is not a retroclone.
Find the system document below or click here to access it in Google Docs. If you are using iOS, it is highly recommended you acquire and use the Google Docs app to open the above link.
It is constantly updated, frequently played, and indefinitely in-development. All comments, questions, and gameplay observations are welcome.