Left-mousers rejoice! After a brief appearance some time ago Razer has decided to listen to fans and bring back the Naga Left-Handed Edition of their popular MMO mouse. All the current (marketing) deets are here https://www2.razer.com/au-en/gaming-mice/razer-naga-left-han.... The price is AU$184.95 with free shipping, which is well within the range of a decent, quality gaming mouse and the same as the right-handed Naga Trinity.
I personally don't play MMOs but I applaud Razer for making an effort to cater for left-mousers. The best I've managed to do thus far is find decent ambidextrous mice, and so far the winner for me has been the Roccat Kova AIMO. I've previously had a Razer Orobourous which I've passed on to a family member and is still going strong, AFAIK.
Let's see if any other major manufacturers get on board, too.