Not saying I work with a lot of Macs or anything, but I see a few thousand a month in my business and if I were you i would seriously reconsider going without some form of AV software these days.
So is there now real evidence of Mac malware? Details please? So far all I see is the odd panic over someone who was fooled into paying for and installing a program that he didn't need. No anti-malware system can protect against that!
If there now IS a real threat, please don't keep the information to yourself!