Nevermind, I see that those ATtiny chips has something called "High Frequency PWM" while the regular Arduino chips don't.
So I wonder, if maybe I could use the Arduino IDE like this:
http://hlt.media.mit.edu/wiki/pmwiki.php?n=Main.ArduinoATtiny4585
But add some extra code to take advantage of those high frequency PWM outputs. The ATtiny45 has 2 High Frequency PWM outputs, which could generate 16-bit High Quality output from the other page above. Just need to figure out the whole thing first. 
Wk