Also, to help with the original post:
I was also looking for a way to backup the original binary so that if all else failed I could just revert to factory settings. I do not intend to modify the original code mostly because the best I'll be able to do is download a hex/binary dump of raw data...not source code.
In my quest, I found this link:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1290093229
I couldn't find if it supported the ATtiny20, but since I don't have an in system programmer yet, I couldn't really try. Could anyone recommend a good ISP for the ATtiny20?
I hope some of this helps.