BareMetal:
hmmm...fasinating as the size issue is, it it entirely irrelevant to my original question!any recommendations for definitive tiny cores other than tom carpenter's?
I believe that Coding Badly's response is the best information you are likely to get. He is the author of the original tiny core that Carpenter based his enhancements on and is probably one of the persons most aware of what is available for the tiny.
If you really want an Arduino tiny core that isn't met by one of the existing implementations, your most likely answer is to build your own. While the tiny series is very useful, there isn't likely to be much demand for an arduino core for all that you ask for. And given that you are the most likely person to put it together.